Bump tomlkit from 0.11.6 to 0.12.3 in /src

Bumps [tomlkit](https://github.com/sdispater/tomlkit) from 0.11.6 to 0.12.3.
- [Release notes](https://github.com/sdispater/tomlkit/releases)
- [Changelog](https://github.com/sdispater/tomlkit/blob/master/CHANGELOG.md)
- [Commits](python-poetry/tomlkit@0.11.6...0.12.3)

---
updated-dependencies:
- dependency-name: tomlkit
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

src/requirements.txt

@@ -76,7 +76,7 @@ toml==0.10.2
     # via
     #   -r src/requirements.txt
     #   pre-commit
-tomlkit==0.11.6
+tomlkit==0.12.3
     # via
     #   -r src/requirements.txt
     #   pylint