github: added announcement comment

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -1,5 +1,9 @@
 name: Bug Report
-description: Create a bug report for pdf2docx
+description: |
+  Create a bug report for pdf2docx
+  Please **_use English language_** only in all your posts and all your issues. Please remember:
+  * We, the maintainers are a team of international experts. You are causing a significant additional amount of work if we have to translate before we can deal with your contributions.
+  * The users of this package are from all over the world. Your valuable insights, comments and examples will mostly be ignored if you do not use English language.
 
 # We omit `title: "..."` so that the field defaults to blank. If we set it to
 # empty string, Github seems to reject this .yml file.