churn: backfilling a branch for LTS 3.0 (#1161)

Author: Timur Sadykov

.github/release-please.yml

@@ -18,3 +18,7 @@ branches:
     handleGHRelease: true
     releaseType: java-backport
     branch: 1.12.x
+  - bumpMinorPreMajor: true
+    handleGHRelease: true
+    releaseType: java-backport
+    branch: 1.6.x

.github/sync-repo-settings.yaml

@@ -68,6 +68,19 @@ branchProtectionRules:
     requiredApprovingReviewCount: 1
     requiresCodeOwnerReviews: true
     requiresStrictStatusChecks: true
+  - pattern: 1.6.x
+    isAdminEnforced: true
+    requiredStatusCheckContexts:
+      - dependencies (8)
+      - dependencies (11)
+      - lint
+      - clirr
+      - units (8)
+      - units (11)
+      - cla/google
+    requiredApprovingReviewCount: 1
+    requiresCodeOwnerReviews: true
+    requiresStrictStatusChecks: true
 permissionRules:
   - team: Googlers
     permission: pull