Docs: Add info about branch protection rules

[usr-icon-foundation]

Please add a notice to the /docs/git-sync/github/ page to make sure that the following branch protection rules are not applied to the branch associated with the Forestry site:

• "Require a pull request before merging"
• "Require signed commits"

Some other rules may conflict with Forestry's intended behavior as well, but I'm not sure. I've only experienced the first one as an issue and am assuming that the second one causes issues as well due to the fact that the Forestry commit messages are not signed