Bug: Running `archivebox update --index-only` doesn't upgrade Snapshot `index.{html,json}` files

#### Describe the bug
I tried to update the `data/archive/<timestamp>/index.{json,html}` files by running the `archivebox update --index-only` command as described in #544. I expected that this command would update the `index.{json,html}` files in the `data/archive/<timestamp>/` folders, but the updated `index.{json,html}` files are only written to `OUTPUT_DIR` and not to the timestamp folder. The updated `index.{json,html}` files in the `OUTPUT_DIR` are probably only used by sonic to create the search index.

#### Steps to reproduce
1. Use `git` on the `archive` folder
2. Run `archivebox update --index-only` (also tried: `archivebox update --index-only --overwrite` but same result)
3. Updated `index.{json,html}` only written to `OUTPUT_DIR`
4. Running `git status` shows no changes to the archive folder
5. `data/archive/<timestamp>/index.{json,html}` files are not updated

#### Screenshots or log output
N/A

#### ArchiveBox version


```logs
ArchiveBox v0.6.2
Cpython Linux Linux-5.13.0-39-generic-x86_64-with-glibc2.29 x86_64
IN_DOCKER=False DEBUG=False IS_TTY=False TZ=UTC SEARCH_BACKEND_ENGINE=sonic

[i] Dependency versions:
 √  ARCHIVEBOX_BINARY     v0.6.2          valid     /usr/local/bin/archivebox                                                   
 √  PYTHON_BINARY         v3.8.10         valid     /usr/bin/python3.8                                                          
 √  DJANGO_BINARY         v3.1.14         valid     /usr/local/lib/python3.8/dist-packages/django/bin/django-admin.py           
 √  CURL_BINARY           v7.68.0         valid     /usr/bin/curl                                                               
 √  WGET_BINARY           v1.20.3         valid     /usr/bin/wget                                                               
 √  NODE_BINARY           v14.19.1        valid     /usr/bin/node                                                               
 √  SINGLEFILE_BINARY     v0.3.32         valid     ./node_modules/single-file/cli/single-file                                  
 √  READABILITY_BINARY    v0.0.3          valid     ./node_modules/readability-extractor/readability-extractor                  
 √  MERCURY_BINARY        v1.0.0          valid     ./node_modules/@postlight/mercury-parser/cli.js                             
 √  GIT_BINARY            v2.25.1         valid     /usr/bin/git                                                                
 -  YOUTUBEDL_BINARY      -               disabled  /usr/local/bin/youtube-dl                                                   
 √  CHROME_BINARY         v100.0.4896.60  valid     /usr/bin/chromium-browser                                                   
 √  RIPGREP_BINARY        v11.0.2         valid     /usr/bin/rg                                                                 

[i] Source-code locations:
 √  PACKAGE_DIR           23 files        valid     /usr/local/lib/python3.8/dist-packages/archivebox                           
 √  TEMPLATES_DIR         3 files         valid     /usr/local/lib/python3.8/dist-packages/archivebox/templates                 
 -  CUSTOM_TEMPLATES_DIR  -               disabled                                                                              

[i] Secrets locations:
 √  CHROME_USER_DATA_DIR  34 files        valid     ./chromium                                                                  
 -  COOKIES_FILE          -               disabled                                                                              

[i] Data locations:
 √  OUTPUT_DIR            13 files        valid     /archive_data/archivebox/data                                               
 √  SOURCES_DIR           112 files       valid     ./sources                                                                   
 √  LOGS_DIR              1 files         valid     ./logs                                                                      
 √  ARCHIVE_DIR           812 files       valid     ./archive                                                                   
 √  CONFIG_FILE           460.0 Bytes     valid     ./ArchiveBox.conf                                                           
 √  SQL_INDEX             6.8 MB          valid     ./index.sqlite3                                                             

```
Config

```
[SERVER_CONFIG]
SECRET_KEY = XXXX
SNAPSHOTS_PER_PAGE = 100

[ARCHIVE_METHOD_TOGGLES]
SAVE_ARCHIVE_DOT_ORG = False
SAVE_MEDIA = False
SAVE_WGET = False
SAVE_READABILITY = True
SAVE_MERCURY = True
SAVE_DOM = True

[ARCHIVE_METHOD_OPTIONS]
CHROME_USER_DATA_DIR = chromium/

[GENERAL_CONFIG]
TIMEOUT = 180

[SEARCH_BACKEND_CONFIG]
SEARCH_BACKEND_ENGINE = sonic
SEARCH_BACKEND_HOST_NAME = localhost
```

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Uh oh!

Bug: Running `archivebox update --index-only` doesn't upgrade Snapshot `index.{html,json}` files #962

Describe the bug

Steps to reproduce

Screenshots or log output

ArchiveBox version

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Uh oh!

Bug: Running archivebox update --index-only doesn't upgrade Snapshot index.{html,json} files #962

Description

Describe the bug

Steps to reproduce

Screenshots or log output

ArchiveBox version

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions

Bug: Running `archivebox update --index-only` doesn't upgrade Snapshot `index.{html,json}` files #962