Don't sign during PR builds

Author: sorenisanerd

.github/workflows/pr.yml

@@ -42,8 +42,6 @@ jobs:
         run: mkosi --debug --profile=build-systemd
       - name: Remove symlinks
         run: find out/ -type l -delete
-      - name: Sign artifacts
-        run: for file in out/* ; do cosign sign-blob -d -y --bundle "${file}.sigbundle" "${file}"; done
       - name: Upload tools artifact
         id: upload-tools
         uses: actions/upload-artifact@v4