Merge branch 'add-default-issue-template' into 'master'

Add a GitLab default issue template.

See merge request asm/asm!334

.gitlab/issue_templates/default.md

-Describe your issue here.
\ No newline at end of file
+<!---
+Before creating a new issue, consider the following (this does not apply to
+feature requests):
+
+- if you need help on how to use ASM, please consult the documentation first
+(https://asm.ow2.io/documentation.html). If you can't find the answer there,
+describe your problem on the http://mail.ow2.org/wws/info/asm mailing listing
+instead of using GitLab issues. The mailing list has more subscribers than the
+GitLab issue tracker, and you will thus likely get a quicker answer via the
+mailing list.
+
+- check if your *input* classes are valid. For this you can use "javap -p -c -v
+<yourclass.class>". If this command fails, the bug is most likely in the tool
+that produced this class, not in ASM. Check the javap output carefully:
+sometimes the tool is able to print most of the class content, but fails to
+parse some part of it. In this case there can be an error message in the middle
+of the javap output, which can be easy to miss at first sight.
+
+- check if you are using the ASM API correctly. For this, insert one or more
+CheckClassAdapter instances in your class generation or class transformation
+chain (in particular, in front of ClassWriter instances). If a CheckClassAdapter
+throws an exception, this means that you are not using the ASM API correctly.
+Fix these issues first.
+
+If you still have a bug after completing the above steps, describe it below and
+make sure to provide detailed instructions on how to reproduce it.
+-->
+
+<!--- Provide a brief summary of the issue in the title above -->
+
+### Expected Behavior
+<!--- Tell us what should happen. -->
+
+### Current Behavior
+<!--- Tell us what happens instead of the expected behavior. -->
+
+### Steps to Reproduce
+<!---
+Provide a self-contained example as an attached archive. If the source code to
+reproduce the issue is very small you can include it here directly (with its
+inputs, most likely some binary .class files, as an attached archive).
+-->