Adds an issue template

ISSUE_TEMPLATE.md

@@ -0,0 +1,10 @@
+<!-- To enable logging to a GitLens channel in the Output pane, set `"gitlens.advanced.output.level": "verbose"` -->
+
+- GitLens Version:
+- VSCode Version:
+- OS Version:
+
+Steps to Reproduce:
+
+1.
+2.