update owlbot lock

Author: tswast

.github/.OwlBot.lock.yaml

@@ -13,5 +13,5 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-python:latest
-  digest: sha256:5581906b957284864632cde4e9c51d1cc66b0094990b27e689132fe5cd036046
+  digest: sha256:4db568eb8ccb6b40f355a1c971876c072b3b160ebade5d913bd29e7976ff7191
 # created: 2025-03-05

.github/sync-repo-settings.yaml

@@ -10,17 +10,16 @@ branchProtectionRules:
     - 'cla/google'
     - 'OwlBot Post Processor'
     - 'lint'
-    - 'Kokoro system-3.8'
+    - 'Kokoro system-3.9'
     - 'Kokoro system-3.11 (noextras)'
     - 'Kokoro system-3.13'
     - 'docs'
-    - 'unit (3.7)'
-    - 'unit (3.8)'
+    - 'unit (3.9)'
     - 'unit (3.12)'
     - 'unit (3.13)'
     - 'cover'
     - 'Samples - Lint'
-    - 'Samples - Python 3.8'
+    - 'Samples - Python 3.9'
     - 'Samples - Python 3.11'
     - 'Samples - Python 3.12'
 permissionRules: