🔨 CI fixes: Bump Checkout to V3, use Python 3.7 and update README Badges

[thisiskeithb]

Description

• CI fixes:
  • Bump Checkout to V3
  • Use Python 3.7
• Update badges in README:
  • Link to License
  • Use last commit as release date and link to master.zip
  • Fix Build Binary CI badge

Note: The Build Binaries action will run after the next PR merge/commit since the .github folder & *.md files are excluded.

Benefits

PR checks & build binary scripts will work again.

Related Issues

None. Noticed that CI tasks were broken again.

[thisiskeithb]

@kisslorand: You should wait to push parts of this PR into your pending PRs since it is not merged and can lead to conflicts.

Once this is merged, rebase your PRs on top of the latest master commit and these changes will be brought in automatically.

[digant73]

@thisiskeithb I see that the bot to mark as stale an Issue or PR after 60 days of inactivity is also not working (so they will never be closed after the configured 7 days). It should be useful to fix that issue if possible. Issues can be marked as resolved by a PR and so automatically closed when the PR is merged but this is not applicable to PRs. Currently there are 14 zombie PRs that should be closed

[thisiskeithb]

@thisiskeithb I see that the bot to mark as stale an Issue or PR after 60 days of inactivity is also not working (so they will never be closed after the configured 7 days). It should be useful to fix that issue if possible. Issues can be marked as resolved by a PR and so automatically closed when the PR is merged but this is not applicable to PRs.

The stale bot that BigTreeTech uses has shut down, so they'll need to migrate to actions/stale.

Currently there are 14 zombie PRs that should be closed

That isn't up to me.

[digant73]

yes, sure it wasn't you. I meant that if you know/could fix also that issue it should be good.

EDIT: Just fixed in https://github.com/bigtreetech/BIGTREETECH-TouchScreenFirmware/pull/2903