[Fix #9124] Update example for rubocop -V of issue template

Fixes #9124.

This PR updates example for `rubocop -V` of issue template.

.github/ISSUE_TEMPLATE/bug_report.md

@@ -32,9 +32,13 @@ a problem will expedite its solution.
 
 ## RuboCop version
 
-Include the output of `rubocop -V` or `bundle exec rubocop -V` if using Bundler. Here's an example:
+Include the output of `rubocop -V` or `bundle exec rubocop -V` if using Bundler.
+If you see extension cop versions (e.g. `rubocop-performance`, `rubocop-rspec`, and others)
+output by `rubocop -V`, include them as well. Here's an example:
 
 ```
 $ [bundle exec] rubocop -V
 1.4.2 (using Parser 2.7.2.0, rubocop-ast 1.1.1, running on ruby 2.7.2 x86_64-linux)
+  - rubocop-performance 1.9.1
+  - rubocop-rspec 2.0.0
 ```

CONTRIBUTING.md

@@ -18,6 +18,8 @@ do so.
 ```
 $ rubocop -V
 1.4.2 (using Parser 2.7.2.0, rubocop-ast 1.1.1, running on ruby 2.7.2 x86_64-linux)
+  - rubocop-performance 1.9.1
+  - rubocop-rspec 2.0.0
 ```
 
 * Include any relevant code to the issue summary.