🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

.kokoro/docker/docs/Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ubuntu:24.04
+from ubuntu:22.04
 
 ENV DEBIAN_FRONTEND noninteractive