Merge meilisearch#1686

1686: Bump milli r=curquiza a=irevoire

 fixes meilisearch#1685, meilisearch#1678, meilisearch#1671, meilisearch#1677 and meilisearch#1680

Co-authored-by: Tamo <tamo@meilisearch.com>

Merge pull request meilisearch#1588 from meilisearch/test-new-indexer

Integrate the new indexer

Merge meilisearch#1636

1636: Hotfix: Log but don't panic when vergen can't retrieve commit information r=curquiza a=Kerollmops

This pull request fixes an issue we discovered when we tried to publish meilisearch v0.21 on brew, brew uses the tarball downloaded from github directly which doesn't contain the `.git` folder.

We use the `.git` folder with [vergen](https://docs.rs/vergen) to retrieve the commit and datetime information. Unfortunately, we were unwrapping the vergen result and it was crashing when the git folder was missing.

We no more panic when vergen can't find the `.git` folder and just log out a potential error returned by [the git2 library](https://docs.rs/git2). We then just check that the env variables are available at compile-time and replace it with "unknown" if not.

### When the `.git` folder is available

```
xh localhost:7700/version
HTTP/1.1 200 OK
Content-Type: application/json
Date: Thu, 26 Aug 2021 13:44:23 GMT
Transfer-Encoding: chunked

{
    "commitSha": "81a76eab69944de8a8d5006345b5aec7b02acf50",
    "commitDate": "2021-08-26T13:41:30+00:00",
    "pkgVersion": "0.21.0"
}
```

### When the `.git` folder is unavailable

```bash
cp -R meilisearch meilisearch-cpy
cd meilisearch-cpy
rm -rf .git
cargo clean
cargo run --release
   <snip>
   Compiling meilisearch-http v0.21.0 (/Users/clementrenault/Documents/meilisearch-cpy/meilisearch-http)
warning: vergen: could not find repository from '/Users/clementrenault/Documents/meilisearch-cpy/meilisearch-http'; class=Repository (6); code=NotFound (-3)
```

```
xh localhost:7700/version
HTTP/1.1 200 OK
Content-Type: application/json
Date: Thu, 26 Aug 2021 13:46:33 GMT
Transfer-Encoding: chunked

{
    "commitSha": "unknown",
    "commitDate": "unknown",
    "pkgVersion": "0.21.0"
}
```

Co-authored-by: Kerollmops <clement@meilisearch.com>

Merge meilisearch#1605

1605: Fix pacic when decoding r=curquiza a=curquiza

Update milli to fix the panic during document deletion

Co-authored-by: Clémentine Urquizar <clementine@meilisearch.com>

Merge meilisearch#1605

1605: Fix pacic when decoding r=curquiza a=curquiza

Update milli to fix the panic during document deletion

Co-authored-by: Clémentine Urquizar <clementine@meilisearch.com>

Merge meilisearch#1596

1596: Update milli and tokenizer version: fix panic during indexation r=curquiza a=curquiza

Fixes meilisearch#1590 

Co-authored-by: Clémentine Urquizar <clementine@meilisearch.com>

Merge meilisearch#1577

1577: Update milli dependency: fix facet values bugs r=Kerollmops a=curquiza

Fixes meilisearch#1576 

Co-authored-by: Clémentine Urquizar <clementine@meilisearch.com>

Merge meilisearch#1554

1554: Fix dump v1 (attributesForFaceting, and criteria) r=curquiza a=MarinPostma

close meilisearch#1553


Co-authored-by: mpostma <postma.marin@protonmail.com>

Merge meilisearch#1540

1540: Update milli to version 0.8.1 r=curquiza a=curquiza

Integrates this fix into MeiliSearch meilisearch/milli#296

Co-authored-by: Clémentine Urquizar <clementine@meilisearch.com>

Merge meilisearch#1481

1481: fix bug in index deletion r=Kerollmops a=MarinPostma

this bug was caused by a heed iterator entry being deleted while still holding a reference to it.


close meilisearch#1333


Co-authored-by: mpostma <postma.marin@protonmail.com>