fix: set changelog author and remove hardcoded entry from spec

Set the rpm-changelog action author to the actual maintainer instead
of the default "Gitea Actions". Remove the static changelog entry
from the spec since the action generates entries automatically.

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

.gitea/workflows/build-release.yml

@@ -99,6 +99,7 @@ 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

rpm/mistralrs.spec

@@ -97,5 +97,3 @@ fi
 %{_sysconfdir}/mistralrs/%{mistralrs_flavour}.conf.example
 
 %changelog
-* Thu Apr 23 2026 Robin Thijssen <grenade@lair.cafe> - %{mistralrs_version}-1
-- Automated build for %{mistralrs_flavour} flavour