chore(package): update @types/execa to version 0.8.1

Author: greenkeeper[bot]

package.json

@@ -40,7 +40,7 @@
     "@knisterpeter/standard-tslint": "^1.6.0",
     "@types/babel-generator": "^6.25.0",
     "@types/diff": "^3.2.2",
-    "@types/execa": "0.8.0",
+    "@types/execa": "0.8.1",
     "@types/node": "^8.0.50",
     "@types/prop-types": "15.5.2",
     "@types/react": "^16.0.21",