Update bug_report.md

Author: willmcgugan

.github/ISSUE_TEMPLATE/bug_report.md

@@ -9,6 +9,8 @@ assignees: ''
 
 Have you checked closed issues? https://github.com/Textualize/textual/issues?q=is%3Aissue+is%3Aclosed
 
+Have you checked against the most recent version of Textual? https://pypi.org/search/?q=textual
+
 Please give a brief but clear explanation of the issue. If you can, include a complete working example that demonstrates the bug. **Check it can run without modifications.**
 
 It will be helpful if you run the following command and paste the results: