Update dependency git-fixtures to v3

Author: renovate-bot

package-lock.json

@@ -65,7 +65,7 @@
     "eslint-plugin-node": "^11.1.0",
     "eslint-plugin-prefer-let": "^1.0.2",
     "git-diff-apply": "0.22.10",
-    "git-fixtures": "^2.3.2",
+    "git-fixtures": "^3.0.0",
     "mocha": "^8.1.3",
     "mocha-helpers": "^5.0.0",
     "renovate-config-standard": "^2.0.0",