fix: migrate MDL resources from getmdl.io to cdnjs.cloudflare.com (#34)

Author: wuhuizuo

pkg/spyglass/lenses/common/static/spyglass-lens.html

@@ -4,7 +4,7 @@
   <meta charset="UTF-8">
   <title>Spyglass Lens: {{.Title}}</title>
   <base href="{{.BaseURL}}" target="_parent">
-  <link rel="stylesheet" href="https://code.getmdl.io/1.3.0/material.indigo-pink.min.css">
+  <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/material-design-lite/1.3.0/material.indigo-pink.min.css">
   <link href="https://fonts.googleapis.com/css?family=Roboto:400,700" rel="stylesheet">
   <link rel="stylesheet" href="https://fonts.googleapis.com/icon?family=Material+Icons">
   <link rel="stylesheet" href="/static/spyglass/lens.css">

pkg/spyglass/lenses/podinfo/template.html

@@ -1,7 +1,7 @@
 {{define "header"}}
 <link rel="stylesheet" type="text/css" href="style.css">
 <script type="text/javascript" src="script_bundle.min.js"></script>
-<script defer src="https://code.getmdl.io/1.3.0/material.min.js"></script>
+<script defer src="https://cdnjs.cloudflare.com/ajax/libs/material-design-lite/1.3.0/material.min.js"></script>
 {{end}}
 
 {{define "body"}}
@@ -237,4 +237,4 @@
     </div>
   </div>
 </div>
-{{end}}
+{{end}}