Require pull requests and approval

[benjaminoakes]

• Require pull request approval
• Don't allow pushes to main

[benjaminoakes]

I added a rule for this but I'm not sure if it's working correctly.

[benjaminoakes]

Testing in #10

[benjaminoakes]

New rule settings:

• Enforcement status: Active
• Target branches: Defaul
• Require a pull request before merging: Checked
  • Additional settings:
    • Required approvals: 1
    • Require review from Code Owners: Checked
• Block force pushes: Checked

I also created a CODEOWNERS file in #11