chore: update tokens workflow (#3954)

Updated the tokens PR workflow to:
- have only one merging branch to prevent overriding changes from the
current month with changes from the past month,
- stop merging the main branch into the token branch, merge it into the
merging branch instead

.github/workflows/create-token-pr.yaml

@@ -25,19 +25,11 @@ jobs:
           git config user.name "Swiss Post Bot"
           git config user.email "[email protected]"
 
-      - name: Update Tokens Branch
-        run: |
-          git checkout ${{ github.ref_name }}
-          git merge origin/main -X ours --no-edit
-          git push
-        env:
-          GITHUB_TOKEN: ${{ secrets.SWISSPOSTDEVS_ACCESS_TOKEN }}
-
-      # Check if a PR branch corresponding to the token branch exists
+      # Check if a PR branch already exists
       - name: Get PR Branch
         id: pr-branch
         run: |
-          PR_BRANCH="merge-tokens-${GITHUB_REF##*/}"
+          PR_BRANCH="update-tokens"
           echo "name=${PR_BRANCH}" >> $GITHUB_OUTPUT
 
           if [[ -n $(git ls-remote origin "${PR_BRANCH}") ]]; then
@@ -46,7 +38,7 @@ jobs:
             echo "exists=false" >> $GITHUB_OUTPUT
           fi
 
-      # If the branch does not exit, create it
+      # If the PR branch does not exit, create it
       - name: Create PR Branch
         if: steps.pr-branch.outputs.exists == 'false'
         run: |
@@ -55,12 +47,19 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.SWISSPOSTDEVS_ACCESS_TOKEN }}
 
-      # If the branch exits, update it
-      - name: Update PR Branch
+      # If the PR branch exits, update it with the tokens branch
+      - name: Update PR Branch with Tokens Branch
         if: steps.pr-branch.outputs.exists == 'true'
         run: |
           git checkout ${{ steps.pr-branch.outputs.name }}
           git merge ${{ github.ref_name }} -X theirs --no-edit
+        env:
+          GITHUB_TOKEN: ${{ secrets.SWISSPOSTDEVS_ACCESS_TOKEN }}
+
+      # Always update the PR branch with the main branch
+      - name: Update PR Branch with main
+        run: |
+          git merge origin/main -X ours --no-edit
           git push
         env:
           GITHUB_TOKEN: ${{ secrets.SWISSPOSTDEVS_ACCESS_TOKEN }}