Base generated release notes on new floating tag 'release'

instead of on the current tag 7.1.2-release.

Author: nat-goodspeed

.github/workflows/build.yaml

@@ -383,7 +383,7 @@ jobs:
           prerelease: true
           generate_release_notes: true
           target_commitish: ${{ github.sha }}
-          previous_tag: 7.1.2-release
+          previous_tag: release
           append_body: true
           fail_on_unmatched_files: true
           files: |