Add issue template

Author: Jon Wayne Parrott

.github/ISSUE_TEMPLATE/new-trove-classifier.md

@@ -0,0 +1,11 @@
+Request to add a new Trove classifier.
+
+## The name of the classifier you would like to add
+<!-- Classifier name -->
+
+## Why do you want to add this classifier?
+<!--
+    Please include a brief explanation to justify your request.
+    Why do the current classifiers not meet your need?
+    How many packages to you expect to use this new classifier?
+-->

warehouse/templates/pages/help.html

@@ -250,7 +250,7 @@ <h3 id="file-name-reuse">{{ file_name_reuse() }}</h3>
 
         <h3 id="new-classifier">{{ new_classifier() }}</h3>
         <p>
-          If you would like to request a new Trove classifer please file a bug on our <a href="https://github.com/pypa/warehouse/issues" target="_blank" rel="noopener">issue tracker</a>. Please include the name of the requested classifier and a brief justification of why it is important.
+          If you would like to request a new Trove classifier please file a bug on our <a href="https://github.com/pypa/warehouse/issues/new?template=new-trove-classifier.md" target="_blank" rel="noopener">issue tracker</a>. Please include the name of the requested classifier and a brief justification of why it is important.
         </p>
         {{ code_of_conduct() }}