ci: bump dependabot target branches

Part of the Nextcloud 24 branch off.
nextcloud/office#5

Signed-off-by: Max <max@nextcloud.com>

.github/dependabot.yml

@@ -23,7 +23,7 @@ updates:
   - 3. to review
   - dependencies
 - package-ecosystem: npm
-  target-branch: stable23
+  target-branch: stable24
   versioning-strategy: lockfile-only
   directory: "/"
   schedule:
@@ -39,7 +39,7 @@ updates:
   - 3. to review
   - dependencies
 - package-ecosystem: npm
-  target-branch: stable22
+  target-branch: stable23
   versioning-strategy: lockfile-only
   directory: "/"
   schedule:
@@ -55,7 +55,7 @@ updates:
   - 3. to review
   - dependencies
 - package-ecosystem: npm
-  target-branch: stable21
+  target-branch: stable22
   versioning-strategy: lockfile-only
   directory: "/"
   schedule: