fix: ignore yarn.lock files in test runs

The lockfile was mispelled as `yarn-lock.json`, when `yarn` actually
uses `yarn.lock` files. We can just ignore them altogether with the
`--no-lockfile` flag.

Author: vvanpo

.gitignore

@@ -25,3 +25,5 @@ pids
 *.pid.lock
 
 package-lock.json
+
+/e2e/__projects__/*/yarn.lock

e2e/__projects__/babel-in-package/yarn.lock

@@ -40,11 +40,8 @@ function runTest(dir) {
     log('Removing node_modules')
     fs.removeSync(`${resolvedPath}/node_modules`)
 
-    log('Removing yarn-lock.json')
-    fs.removeSync(`${resolvedPath}/yarn-lock.json`)
-
     log('Installing node_modules')
-    run('yarn install --silent')
+    run('yarn install --silent --no-lockfile')
   }
 
   // For tests that need vue-jest to successfully `require.resolve()` a file in