refactor(execa): account for breaking change in execa

Author: travi

Diff for: lib/exec.js

@@ -1,6 +1,6 @@
 import { resolve } from "path";
 import { template } from "lodash-es";
-import execa from "execa";
+import { execa } from "execa";
 
 export default async function exec(
   cmdProp,