feat: next release from main branch is 1.121.0 (#1406)

Author: mmicatka

.github/release-please.yml

@@ -22,3 +22,7 @@ branches:
     handleGHRelease: true
     releaseType: java-backport
     branch: 1.117.x
+  - bumpMinorPreMajor: true
+    handleGHRelease: true
+    releaseType: java-backport
+    branch: 1.120.x

.github/sync-repo-settings.yaml

@@ -100,6 +100,24 @@ branchProtectionRules:
       - Kokoro - Against Pub/Sub Lite samples
       - cla/google
       - OwlBot Post Processor
+  - pattern: 1.120.x
+    isAdminEnforced: true
+    requiredApprovingReviewCount: 1
+    requiresCodeOwnerReviews: true
+    requiresStrictStatusChecks: false
+    requiredStatusCheckContexts:
+      - dependencies (8)
+      - dependencies (11)
+      - lint
+      - clirr
+      - units (8)
+      - units (11)
+      - 'Kokoro - Test: Integration'
+      - Kokoro - Against Pub/Sub Lite samples
+      - cla/google
+      - OwlBot Post Processor
+      - 'Kokoro - Test: Java GraalVM Native Image'
+      - 'Kokoro - Test: Java 17 GraalVM Native Image'
 permissionRules:
   - team: yoshi-admins
     permission: admin