chore: add repo settings (#114)

Author: jpoehnelt

.github/sync-repo-settings.yaml

@@ -0,0 +1,12 @@
+rebaseMergeAllowed: true
+squashMergeAllowed: true
+mergeCommitAllowed: false
+deleteBranchOnMerge: true
+branchProtectionRules:
+- pattern: main
+  requiredStatusCheckContexts:
+    - 'cla/google'
+  requiredApprovingReviewCount: 1
+  requiresCodeOwnerReviews: true
+  requiresStrictStatusChecks: false
+  isAdminEnforced: false