Fix issue #49 Plumrocket\Amp... not found

Author: ihorvansach

Block/Amp/Ldjson/PostList.php

@@ -11,7 +11,13 @@
 /**
  * Blog post list ldJson block
  */
-class PostList extends \Plumrocket\Amp\Block\Page\Head\Ldjson\Cms
+if (class_exists('\Plumrocket\Amp\Block\Page\Head\Ldjson\Cms')) {
+    class PostListIntermediate extends \Plumrocket\Amp\Block\Page\Head\Ldjson\Cms {}
+} else {
+    class PostListIntermediate extends \Magento\Framework\View\Element\AbstractBlock {}
+}
+
+class PostList extends PostListIntermediate
 {
     /**
      * Retrieve page structure structure data in JSON

Block/Amp/Og/Post.php

@@ -12,7 +12,14 @@
 /**
  * Blog post opengraph for amp
  */
-class Post extends \Plumrocket\Amp\Block\Page\Head\Og\AbstractOg
+
+if (class_exists('\Plumrocket\Amp\Block\Page\Head\Og\AbstractOg')) {
+    class PostIntermediate extends \Plumrocket\Amp\Block\Page\Head\Og\AbstractOg {}
+} else {
+    class PostIntermediate extends \Magento\Framework\View\Element\AbstractBlock {}
+}
+
+class Post extends PostIntermediate
 {
     /**
      * Retrieve open graph params