Show proper version for lightweight tags (#2152)

Our Git Webpack plugin supports lightweight tags, but we don't have the
right configuration options set to enable it. This PR enables support
for lightweight tags.

webpack.mix.js

@@ -64,7 +64,9 @@ const webpack_plugins = [
 
 if (git_clone) {
   const { GitRevisionPlugin } = require('git-revision-webpack-plugin');
-  webpack_plugins.push(new GitRevisionPlugin());
+  webpack_plugins.push(new GitRevisionPlugin({
+    lightweightTags: true,
+  }));
 }
 
 // Copy angularjs files to build directory.