docs: remove old issue template

.github/ISSUE_TEMPLATE.md

@@ -1,12 +0,0 @@
-<!-- Wiki.js 1.x? Go to https://github.com/Requarks/wiki-v1/issues -->
-
-### Actual behavior
-
-### Expected behavior
-
-### Steps to reproduce the behavior
-
-<!-- FOR FEATURE REQUESTS: Use the feature request board instead: https://requests.requarks.io/wiki -->
-
-<!-- Love Wiki.js? Please consider supporting our collective:
-👉  https://opencollective.com/wikijs/donate -->