Adds proper check for script existing in bolt workspace run command

Author: lukebatchelor

example/package.json

@@ -1,9 +1,9 @@
 {
   "private": true,
   "name": "fixture-project",
-  "pworkspaces": [
-    "packages/*"
-  ],
+  "bolt": {
+    "workspaces": ["packages/*"]
+   },
   "dependencies": {
     "react": "^15.6.1"
   }

example/packages/foo/package.json

@@ -7,9 +7,9 @@
     "postinstall": "echo postinstall",
     "prepublish": "echo prepublish"
   },
-  "pworkspaces": [
-    "packages/*"
-  ],
+  "bolt": {
+    "workspaces": ["packages/*"]
+  },
   "dependencies": {
     "react": "^15.6.1",
     "bar-workspace-package": "^1.0.0"

src/commands/workspace/run.js

@@ -39,12 +39,13 @@ export async function workspaceRun(opts: WorkspaceRunOptions) {
     );
   }
 
-  let validScript = await yarn.run(workspace.pkg, opts.script, opts.scriptArgs);
+  let validScript = await yarn.getScript(workspace.pkg, opts.script);
 
   if (!validScript) {
     throw new BoltError(
       `Package at "${workspace.pkg
         .dir}" does not have a script named "${opts.script}"`
     );
   }
+  await yarn.run(workspace.pkg, opts.script, opts.scriptArgs);
 }