Update doc/CONTRIBUTING.md

Co-authored-by: Copilot <[email protected]>

Author: compwron

doc/CONTRIBUTING.md

@@ -2,7 +2,7 @@
 
 We ♥ contributors! By participating in this project, you agree to abide by the Ruby for Good [code of conduct](https://github.com/rubyforgood/code-of-conduct).
 
-If you have any questions about an issue, comment on the issue, open a new issue or ask in [the RubyForGood slack](https:https://join.slack.com/t/rubyforgood/shared_invite/zt-35218k86r-vlIiWqig54c9t~_LkGpQ7Q). CASA has a `#casa` channel in the Slack. Our channel in slack also contains a zoom link for office hours every day office hours are held.
+If you have any questions about an issue, comment on the issue, open a new issue or ask in [the RubyForGood slack](https://join.slack.com/t/rubyforgood/shared_invite/zt-35218k86r-vlIiWqig54c9t~_LkGpQ7Q). CASA has a `#casa` channel in the Slack. Our channel in slack also contains a zoom link for office hours every day office hours are held.
 
 You won't be yelled at for giving your best effort. The worst that can happen is that you'll be politely asked to change something. We appreciate any sort of contributions, and don't want a wall of rules to get in the way of that.