build: fix semver/none label on appveyor update PR (#38647)

.github/workflows/update_appveyor_image.yml

@@ -68,7 +68,7 @@ jobs:
         delete-branch: true
         reviewers: electron/wg-releases
         title: 'build: update appveyor image to latest version'
-        labels: semver-none,no-backport
+        labels: semver/none,no-backport
         body: |
           This PR updates appveyor.yml to the latest baked image, ${{ env.APPVEYOR_IMAGE_VERSION }}.
-          Notes: none
+          Notes: none