fix(deps): update dependency execa to v3 (#251)

Author: renovate-bot

packages/google-cloud-automl/samples/package.json

@@ -21,7 +21,7 @@
     "@google-cloud/automl": "^1.5.0",
     "chai": "^4.2.0",
     "csv": "^5.1.1",
-    "execa": "^2.0.0",
+    "execa": "^3.0.0",
     "mathjs": "^6.0.0",
     "yargs": "^14.0.0"
   },