Bump tensorflow from 2.8.0rc1 to 2.8.0 in /extra_requirements (#949)

Bumps [tensorflow](https://github.com/tensorflow/tensorflow) from 2.8.0rc1 to 2.8.0.
- [Release notes](https://github.com/tensorflow/tensorflow/releases)
- [Changelog](https://github.com/tensorflow/tensorflow/blob/master/RELEASE.md)
- [Commits](tensorflow/tensorflow@v2.8.0-rc1...v2.8.0)

---
updated-dependencies:
- dependency-name: tensorflow
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

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

extra_requirements/requirements-tests.txt

@@ -33,7 +33,7 @@ pytest==7.0.1
 pytest-cov==3.0.0
 scikit-learn==1.0.2
 scipy==1.7.3                                    # Strax dependency
-tensorflow==2.8.0rc1; python_version<="3.9"
+tensorflow==2.8.0; python_version<="3.9"
 tensorflow==2.8.0rc1; python_version=="3.10"
 tqdm==4.62.2
 typing_extensions==4.1.1                        # Tensorflow/bokeh dependency