fix(deps): update dependency @actions/artifact to v6

Author: renovate[bot]

.github/actions/file-diff/package.json

@@ -22,7 +22,7 @@
     "package.json"
   ],
   "dependencies": {
-    "@actions/artifact": "2.3.2",
+    "@actions/artifact": "6.1.0",
     "@actions/core": "1.11.1",
     "@actions/github": "6.0.1",
     "@actions/glob": "0.6.1",