Add retry to Certbot installation with package

[ChrisHills463]

Add a retry to the "Install Certbot." task which can fail if there is another process that has locked the package updater (e.g. install 'certbot'' failed: E: Could not get lock /var/lib/dpkg/lock-frontend. It is held by process 11425 (unattended-upgr))

[github-actions[bot]]

This pr has been marked 'stale' due to lack of recent activity. If there is no further activity, the issue will be closed in another 30 days. Thank you for your contribution!

Please read this blog post to see the reasons why I mark issues as stale.

[github-actions[bot]]

This pr has been closed due to inactivity. If you feel this is in error, please reopen the issue or file a new issue with the relevant details.