fix: remove explicit author override from changelog action

Let the action use its default author rather than misattributing
upstream commits to the package maintainer.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/workflows/build-release.yml

@@ -99,7 +99,6 @@ jobs:
         with:
           spec: rpm/mistralrs.spec
           version: ${{ steps.version.outputs.version }}
-          author: "Robin Thijssen <grenade@lair.cafe>"
           repo-url: https://github.com/EricLBuehler/mistral.rs.git
 
       - name: Build RPM