Merge pull request #259 from nkubala/maintainers

Add maintainers file and new issue template

Author: nkubala

.github/CODEOWNERS

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+* @nkubala @dlorenc @aaron-prindle

.github/ISSUE_TEMPLATE.md

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+<!-- 
+  Issues without logs and details are more complicated to fix.
+  Please help us by filling the template below!
+-->
+
+### Expected behavior
+
+### Actual behavior
+
+### Information
+
+- container-diff version: version...
+- Operating system: ...
+
+### Steps to reproduce the behavior
+
+1. ...
+2. ...