Create pull_request_template.md

Signed-off-by: Jan Kowalleck <[email protected]>

Author: jkowalleck

.github/pull_request_template.md

@@ -0,0 +1,18 @@
+<!-- 
+Thank you for taking the time to developing and donate a feature or core enhancement.
+
+We would kindly ask you to create pull-requests only for things that were discussed in a ticket, first.
+So please have the related ticket/issue id handy. 
+If there is none, feel free to create a new ticket: https://github.com/CycloneDX/specification/issues/new/choose
+-->
+
+<!-- 
+
+Please write a short desciption of what the pull-requet intends to do and which ticket it fixes/closes.
+
+Examepl:
+>  As discussed in ticket #485, this PR adds Streebog to the hash algorithm enum.
+>
+>  fixes #485
+
+-->