feat: setup 1.43.x lts branch (#1869)

Author: burkedavison

.github/release-please.yml

@@ -18,3 +18,7 @@ branches:
     handleGHRelease: true
     releaseType: java-backport
     branch: 1.42.x
+  - bumpMinorPreMajor: true
+    handleGHRelease: true
+    releaseType: java-backport
+    branch: 1.43.x

.github/sync-repo-settings.yaml

@@ -70,6 +70,20 @@ branchProtectionRules:
       - dependencies (11)
       - clirr
       - cla/google
+  - pattern: 1.43.x
+    isAdminEnforced: true
+    requiredApprovingReviewCount: 1
+    requiresCodeOwnerReviews: true
+    requiresStrictStatusChecks: false
+    requiredStatusCheckContexts:
+      - units (7)
+      - units (8)
+      - units (11)
+      - windows
+      - dependencies (8)
+      - dependencies (11)
+      - clirr
+      - cla/google
 permissionRules:
   - team: yoshi-admins
     permission: admin