Update execa to 4.0.3.

Author: Robert Jackson

package.json

@@ -20,7 +20,7 @@
     "test": "jest"
   },
   "dependencies": {
-    "execa": "^4.0.2",
+    "execa": "^4.0.3",
     "gitconfiglocal": "^2.1.0",
     "github-label-sync": "^1.6.0",
     "hosted-git-info": "^3.0.5",