ci: bump softprops/action-gh-release from v2 to v4

Fixes Node.js 20 deprecation warning on release pipeline.

Author: molty3000

.github/workflows/release.yml

@@ -48,7 +48,7 @@ jobs:
         run: sha256sum odek-* > checksums.txt
 
       - name: release
-        uses: softprops/action-gh-release@v2
+        uses: softprops/action-gh-release@v4
         with:
           files: |
             odek-linux-amd64