Bump git/ext/gitdb from 335c0f6 to 39d7dbf

Bumps [git/ext/gitdb](https://github.com/gitpython-developers/gitdb) from `335c0f6` to `39d7dbf`.
- [Release notes](https://github.com/gitpython-developers/gitdb/releases)
- [Commits](gitpython-developers/gitdb@335c0f6...39d7dbf)

---
updated-dependencies:
- dependency-name: git/ext/gitdb
  dependency-version: 39d7dbf285df058e44ea501c23ea8d31ae8bce0e
  dependency-type: direct:production
...

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Author: dependabot[bot]