adds pr templates

Author: abhi1693

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,17 @@
+<!--
+    Thank you for your interest in contributing to pynetbox! Please note that
+    our contribution policy requires that a feature request or bug report be
+    approved and assigned prior to opening a pull request. This helps avoid
+    waste time and effort on a proposed change that we might not be able to
+    accept.
+
+    IF YOUR PULL REQUEST DOES NOT REFERENCE AN ISSUE WHICH HAS BEEN ASSIGNED
+    TO YOU, IT WILL BE CLOSED AUTOMATICALLY.
+
+    Please specify your assigned issue number on the line below.
+-->
+### Fixes: #1234
+
+<!--
+    Please include a summary of the proposed changes below.
+-->