Merge pull request python-gitlab#1418 from python-gitlab/fix/urlencod…

…e-file-paths

fix(files): do not url-encode filepaths twice

Merge pull request python-gitlab#1408 from python-gitlab/chore/bump-t…

…o-2-7-0

chore: bump version to 2.7.0

Merge pull request python-gitlab#1273 from python-gitlab/chore/python3-9

chore: offically support and test 3.9