New Github Actions

[DavidHerreros]

• Prevent branches from merging PR to main. Only PR from dev can be merged
• Publish new release to Pypi and tag new version in the repository (currently will not work)

[DavidHerreros]

After merging this PR, it will not be possible to merge branches into main unless the PR is coming from dev. Therefore, this PR will stablish the following workflow for future releases:

new_branch -> dev -> main -> New release (Pypi and tag)

As it can be seen from the checks, Check merging branch will fail as the PR is not coming from devel. Once this is merge, there will be a ruleset for main that will ensure that all checks (including as well Check merging branch) have been passed succesfully before allowing to merge.

[DavidHerreros]

Please @geoffwoollard, could you check if these changes make sense before marking this PR as "Ready for review".

Also, I would not merge this until everything is ready to be released into Pypi. To do that, some extra configuration in the repo will be needed (we can discuss about this configuration changes on a separate issue).

[geoffwoollard]

The fact I'm seeing this, means it's working.

We'll also have to check that dev can indeed merge into main... (once this is merged).

[geoffwoollard]

Closes #30