Enable GitHub Actions on the 3.10 branch by hugovk · Pull Request #26242 · python/cpython
Like #20231 but for 3.10.
Also YAML would interpret 3.10 (no quotes) as a float and look for 3.1, which obviously won't work!
So this also adds quotes to ensure they're correctly treated as strings.
Should adding the new version to CI YAML files be included in a beta branching checklist?