Update CONTRIBUTING.md from dry-rb/template-gem

Author: Action Hero

CONTRIBUTING.md

@@ -10,7 +10,7 @@ Report a feature request **only after discussing it first on [discourse.dry-rb.o
 
 ## Reporting questions, support requests, ideas, concerns etc.
 
-**PLEASE DON'T** - use [discourse.dry-rb.org](http://discourse.dry-rb.org) instead.
+**PLEASE DON'T** - use [discourse.dry-rb.org](https://discourse.dry-rb.org) instead.
 
 # Pull Request Guidelines