build: fix security warnings and update dependencies

- remove CodePen iframe from Getting Started guide since they are
  now blocking embeds via `sameorigin`
- update some other dependencies like postcss, lodash, graceful-fs, jquery,
  eslint, dgeni, autoprefixer, and conventional-changelog
- before: found 18 vulnerabilities (9 low, 1 moderate, 8 high)
- after: found 14 vulnerabilities (7 low, 1 moderate, 6 high)

Closes #12084

Author: Splaktar

docs/app/partials/getting-started.tmpl.html

@@ -44,7 +44,7 @@ <h2>How do I start with AngularJS Material?</h2>
       </li>
       <li style="margin-bottom: 30px;">
         Checkout the <a href="https://github.com/angular/material-start/tree/typescript" target="_blank"
-           title="Material Start - Typescript and SystemJS">AngularJS Material TypeScript + SystemJS</a>
+           title="Material Start - Typescript and SystemJS">AngularJS Material + TypeScript + SystemJS</a>
         repository
       </li>
       <li>Use the "Edit on CodePen" button on any of our Demos<br/>
@@ -59,17 +59,9 @@ <h3>Our CodePen Community</h3>
       <a href="https://codepen.io/team/AngularMaterial/" target="_blank"
          title="Codepen Community">CodePen Community</a> to explore more
       <a href="https://codepen.io/team/AngularMaterial/pens/public/" target="_blank">samples</a>,
-      <a href="https://codepen.io/team/AngularMaterial/collections/public/" target="_blank">Collections</a>, and ideas.
+      <a href="https://codepen.io/team/AngularMaterial/collections/public/" target="_blank">collections</a>, and ideas.
     </p>
-    <div layout-align="center" style="width: 100%">
-      <iframe height='777' scrolling='no' title="Our CodePen Community"
-            src='https://codepen.io/collection/XExqGz/'
-            frameborder='no' allowtransparency='true' allowfullscreen='true' style='width: 100%;'>
-      </iframe>
-    </div>
-
-
-    <br/><br/>
+    <br/>
 
     <h3>Installing the AngularJS Material Libraries</h3>