GitHub action versions

[hombit]

Currently we have both github actions versions set to @main and dependabot configuration file which is supposed to update the versions. These two don't play well together.

So we should either

1. Remove dependabot updates for github actions, because they never trigger
2. Switch back from @main to @vX to make sure people do not use some non-released version of an action, and would not have an issue with backward-incompatible updates. However, dependabot could be annoying and backward-incompatibility in popular actions is a rear thing