Update issue_template.md (#180)

Author: vwxyzjn

.github/issue_template.md

@@ -1,6 +1,10 @@
 ## Problem Description
 <!--- Provide a general summary of the issue in the Title above -->
 
+## Checklist
+- [ ] I have installed dependencies via `poetry install` (see [CleanRL's installation guideline](https://docs.cleanrl.dev/get-started/installation/).
+- [ ] I have checked that there is no similar [issue](https://github.com/vwxyzjn/cleanrl/issues) in the repo (required)
+
 ## Current Behavior
 <!--- Tell us what happens instead of the expected behavior -->