Bump firebase-admin from 6.0.1 to 6.1.0 (#109)

Bumps [firebase-admin](https://github.com/firebase/firebase-admin-python) from 6.0.1 to 6.1.0.
- [Release notes](https://github.com/firebase/firebase-admin-python/releases)
- [Commits](firebase/firebase-admin-python@v6.0.1...v6.1.0)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

doc/requirements.txt

@@ -15,4 +15,4 @@ scipy==1.7.3
 moabb>=0.4.6
 git+https://github.com/pyRiemann/pyRiemann#egg=pyriemann
 docplex>=2.21.207
-firebase_admin==6.0.1
+firebase_admin==6.1.0