Add repo roles: (#17)

## Description


This is needed to enable the repo roles defined by the community here: tinkerbell/org#10

## Why is this needed



Fixes: #

## How Has This Been Tested?





## How are existing users impacted? What migration steps/scripts do we need?





## Checklist:

I have:

- [ ] updated the documentation and/or roadmap (if required)
- [ ] added unit or e2e tests
- [ ] provided instructions on how to upgrade

Author: mergify[bot]

.github/CODEOWNERS

@@ -0,0 +1,2 @@
+/.github/settings.yml @mmlb
+/.github/CODEOWNERS @mmlb

.github/settings.yml

@@ -0,0 +1,20 @@
+# Collaborators: give specific users access to this repository.
+# See https://docs.github.com/en/rest/reference/repos#add-a-repository-collaborator for available options
+collaborators:
+  # Maintainers, should also be added to the .github/CODEOWNERS file as owners of this settings.yml file.
+  - username: mmlb
+    permission: maintain
+  # Approvers
+  - username: tstromberg
+    permission: push
+  # Reviewers
+  - username: rawkode
+    permission: triage
+
+  # Note: `permission` is only valid on organization-owned repositories.
+  # The permission to grant the collaborator. Can be one of:
+  # * `pull` - can pull, but not push to or administer this repository.
+  # * `push` - can pull and push, but not administer this repository.
+  # * `admin` - can pull, push and administer this repository.
+  # * `maintain` - Recommended for project managers who need to manage the repository without access to sensitive or destructive actions.
+  # * `triage` - Recommended for contributors who need to proactively manage issues and pull requests without write access.