build: further revert execa's version

Author: feywind

package.json

@@ -80,7 +80,7 @@
     "@types/uuid": "^10.0.0",
     "c8": "^10.1.3",
     "codecov": "^3.8.3",
-    "execa": "^5.1.1",
+    "execa": "~5.0.0",
     "gapic-tools": "^1.0.1",
     "gts": "^6.0.2",
     "jsdoc": "^4.0.4",