ci: preserve full Linux package suffixes

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Signed-off-by: Favilances Noir <favilances@proton.me>

Author: melihemik

.github/workflows/build-release.yml

@@ -127,8 +127,8 @@ jobs:
           set -euo pipefail
           mkdir -p release-assets
           for f in dist/differ-linux-x64.*; do
-            ext="${f##*.}"
-            cp "$f" "release-assets/differ-${ASSET_SUFFIX}-linux-x64.${ext}"
+            suffix="${f#dist/differ-linux-x64.}"
+            cp "$f" "release-assets/differ-${ASSET_SUFFIX}-linux-x64.${suffix}"
           done
 
       - name: Upload Linux packages