ci: clear SPM artifacts cache in release workflow

Match the fix from PR #119 for dev-build and tests workflows.
The macos-26 runner image can pre-populate SPM binary artifact
caches that cause Sparkle download failures.

Author: sozercan

.github/workflows/release.yml

@@ -41,6 +41,9 @@ jobs:
       - name: Show Swift version
         run: swift --version
 
+      - name: Clear SPM artifacts cache
+        run: rm -rf ~/Library/Caches/org.swift.swiftpm/artifacts
+
       - name: Run unit tests
         run: swift test -q --skip KasetUITests