Update app.yaml

Nodejs18 has reached EOL. Updating to 22

Author: kindavishal

app/app.yaml

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-runtime: nodejs18
+runtime: nodejs22
 handlers:
 # Serve all static files with url ending with a file extension
 - url: /(.*\..+)$