fix: remove mention of issues in CONTRIBUTING.md

Currently issues are locked down due to spam.  We will remove for now
but may readd if we open issues.

Thank you michael-hawker for catching this.

Signed-off-by: jmeridth <jmeridth@gmail.com>
Co-authored-by: "Michael Hawker MSFT (XAML Llama)" <24302614+michael-hawker@users.noreply.github.com>

Author: jmeridth

CONTRIBUTING.md

@@ -69,6 +69,6 @@ chmod +x script/server
 
 ## Community
 
-Discussions about the Open Source Guides take place on this repository's [Issues](https://github.com/github/opensource.guide/issues) and [Pull Requests](https://github.com/github/opensource.guide/pulls) sections. Anybody is welcome to join these conversations.
+Discussions about the Open Source Guides take place on this repository's [Pull Requests](https://github.com/github/opensource.guide/pulls) section. Anybody is welcome to join these conversations.
 
 Wherever possible, do not take these conversations to private channels, including contacting the maintainers directly. Keeping communication public means everybody can benefit and learn from the conversation.