docs: add a GitHub issue template

Signed-off-by: Joakim Bech <[email protected]>
Acked-by: Jerome Forissier <[email protected]>

Author: jbech-linaro

.github/issue_template.md

@@ -0,0 +1,21 @@
+<!--
+    General guidance when creating issues:
+
+    1. Please try to remember to close the issue when you have
+       got an answer to your question.
+
+    2. It never hurts to state which commit or release tag you are using in case
+       the question is about build issues.
+
+    3. Try to use GitHub markdown formatting to make your issue more readable:
+         https://help.github.com/articles/basic-writing-and-formatting-syntax/#quoting-code
+
+    4. Try to search for the issue before posting the question:
+         -> Issues tab -> Filters
+
+    5. Check the FAQ before posting a question:
+         https://www.op-tee.org/faq
+
+    NOTE: This comment will not be shown in the issue, so no harm keeping it,
+    but feel free to remove it if you like.
+-->