Fix various action warnings from CI builds

[hodgestar]

See, for example, the warnings at the bottom of the summary page https://github.com/qutip/qutip-tutorials/actions/runs/3518209568.

These actions seem to be mostly be generated from actions defined elsewhere that we're using. Hopefully we can either use newer versions of them, replace them with ones supplied directly by GitHub, or replace them with a few lines of shell script in the CI .yml file.