ci: Update Github's actions to latest version

[taratatach]

Some of our actions use deprecated syntax that will soon be disabled.

Please make sure the following boxes are checked:

• [x] PR is not too big
• [x] it improves UX & DX in some way
• [ ] it includes unit tests matching the implementation changes
• [ ] it includes scenarios matching a new behaviour or has been manually tested
• [x] it includes relevant documentation