Fix headings structure for workshop posts

Author: josenino95

layouts/workshop/single.html

@@ -1,5 +1,5 @@
 {{ define "main" }}
-    <h3>{{ .Title }}</h3>
+    <h2>{{ .Title }}</h2>
 
     <div class="details">
         <p style="margin:0;font-weight:bold">{{ .Params.human_date }}, {{ .Params.year }}</p>
@@ -39,7 +39,7 @@ <h3>{{ .Title }}</h3>
     <hr style="border: none; border-top: 3px solid #ddd; margin: 20px 0;">
 
     <div class="survey-links">
-        <h4>Surveys</h4>
+        <h3>Surveys</h3>
         <p>Please be sure to complete these surveys before and after the
         workshop.</p>
         <p>
@@ -56,7 +56,7 @@ <h4>Surveys</h4>
     <hr style="border: none; border-top: 3px solid #ddd; margin: 20px 0;">
 
     <div class="conduct">
-        <h4>Code of Conduct</h4>
+        <h3>Code of Conduct</h3>
         <p> Everyone who participates in Carpentries activities is required to
         conform to the Code of Conduct. This document also outlines how to
         report an incident if needed.</p>
@@ -71,15 +71,15 @@ <h4>Code of Conduct</h4>
     <hr style="border: none; border-top: 3px solid #ddd; margin: 20px 0;">
 
     <div class="schedule">
-        <h4>Schedule</h4>
+        <h3>Schedule</h3>
         <p>{{ . | markdownify }}</p>
     </div>
     {{ end }}
 
     {{ with .Params.instructions }}
     <hr style="border: none; border-top: 3px solid #ddd; margin: 20px 0;">
     <div class="instructions">
-        <h4>Workshop prep instructions:</h4>
+        <h3>Workshop prep instructions:</h3>
         <p>{{ . | markdownify }}</p>
     </div>
     {{ end }}