ci: enhance changelog update step with previous tag reference

- Added step to retrieve the previous tag for more accurate changelog generation.

Author: QuadStingray

.github/workflows/main_test_release.yml

@@ -69,7 +69,7 @@ jobs:
       - name: Get previous tag
         id: previousTag
         run: |
-          name=$(git --no-pager tag --sort=creatordate --merged ${{ github.ref_name }} | tail -2 | head -1)
+          name=$(git --no-pager tag --sort=creatordate --merged ${{ github.ref_name }} | tail -1 | head -1)
           echo "previousTag: $name"
           echo "previousTag=$name" >> $GITHUB_ENV