add pull_request_template.md

Author: smiklosovic

.github/issue_template.md

@@ -0,0 +1,23 @@
+Thanks for sending a pull request! Here are some tips if you're new here:
+
+ * Reflect JIRA ticket number in the pull request title 
+ * Be sure to keep the PR description updated to reflect all changes.
+ * Write your PR title to summarize what this PR proposes.
+ * If possible, provide a concise example to reproduce the issue for a faster review.
+ 
+Commit messages should follow the following format:
+
+```
+<One sentence description, usually Jira title or CHANGES.txt summary>
+
+<Optional lengthier description (context on patch)>
+
+patch by <Authors>; reviewed by <Reviewers> for CASSANDRA-#####
+
+Co-authored-by: Name1 <email1>
+Co-authored-by: Name2 <email2>
+
+```
+
+The [Cassandra Jira](https://issues.apache.org/jira/projects/CASSANDRA/issues/)
+