Update backport workflow configuration

Updated backport workflow to use new reusable-backport.yml version and changed secret keys.

Author: linawolf

.github/workflows/backport.yml

@@ -11,8 +11,9 @@ permissions:
 
 jobs:
   backport:
-    uses: TYPO3-Documentation/.github/.github/workflows/reusable-backport.yml@e2ccd27accf9ee90f8eca7e037a12fabe089b51b
+    uses: TYPO3-Documentation/.github/.github/workflows/reusable-backport.yml@b43f22b27bea079a6ebc0180d570424de305037a
     with:
       label_pattern: "^backport (.+)$"
     secrets:
-      BOT_TOKEN: ${{ secrets.BOT_TOKEN }}
+      APP_ID: ${{ secrets.APP_ID }}
+      APP_PRIVATE_KEY: ${{ secrets.APP_PRIVATE_KEY }}