Update to Hugo 0.53 and remove all .Site references (#12079)

* Remove all .Site variable references

* Update Hugo version in Travis CI config and Makefile

layouts/docs/docsportal_home.html

@@ -38,7 +38,7 @@
 
       <div class="launch-card">
         <h4>Try Kubernetes</h4>
-        
+
         <p>Follow tutorials to learn how to deploy applications in Kubernetes.</p>
         <br>
         <ul>
@@ -53,7 +53,7 @@
 
       <div class="launch-card">
         <h4>Set up a cluster</h4>
-        
+
         <p>Get Kubernetes running based on your resources and needs.</p>
         <br>
         <ul>
@@ -70,7 +70,7 @@
 
       <div class="launch-card">
         <h4>Learn how to use Kubernetes</h4>
-        
+
         <p>Look up common tasks and how to perform them using a short sequence of steps.</p>
         <br>
         <ul>
@@ -86,7 +86,7 @@
 
       <div class="launch-card">
         <h4>Look up reference information</h4>
-        
+
         <p>Browse terminology, command line syntax, API resource types, and setup tool documentation.</p>
         <br>
         <ul>
@@ -102,7 +102,7 @@
 
       <div class="launch-card">
         <h4>Contribute to the docs</h4>
-        
+
         <p>Anyone can contribute, whether you’re new to the project or you’ve been around a long time.</p>
         <br>
         <ul>
@@ -118,7 +118,7 @@
 
       <div class="launch-card">
         <h4>Download Kubernetes</h4>
-        
+
         <p>If you are installing Kubernetes or upgrading to the newest version, refer to the current release notes.</p>
         <br>
         <ul>
@@ -130,7 +130,7 @@
 
       <div class="launch-card">
         <h4>About the documentation</h4>
-        
+
         <p>This website contains documentation for the current and previous 4 versions of Kubernetes.</p>
         <br>
         <ul>

layouts/docs/glossary.html

@@ -10,12 +10,12 @@
 <div id="tag-container">
 	<p>Filter terms according to their tags:</p>
 	<div class="tag-description invisible" id="placeholder">.</div>
-	{{ range (index .Site.Data "canonical-tags") }}
+	{{ range (index site.Data "canonical-tags") }}
 	<div class="tag-description hide" id="{{ printf "tag-%s-description" .id  }}">
 		<i>{{ .description }}</i>
 	</div>
 	{{ end }}
-	{{ $sorted_tags := sort (index .Site.Data "canonical-tags") "name" }}
+	{{ $sorted_tags := sort (index site.Data "canonical-tags") "name" }}
 	{{ range $sorted_tags }}
 	{{ $full_tag_name := printf "tag-%s" .id }}
 	<span id="{{ $full_tag_name  }}" class="tag-option canonical-tag" data-target="{{ $full_tag_name  }}">