chore: GitHub casing (#3496)

Author: iiio2

CONTRIBUTING.md

@@ -8,7 +8,7 @@
 
 You can involve in discussions using:
 
-- [Github Discussions](discussions)
+- [GitHub Discussions](discussions)
 - [Nitro Discord](https://discord.nitro.build)
 
 ## Contribute to the Code

docs/2.deploy/20.providers/deno-deploy.md

@@ -21,7 +21,7 @@ cd .output
 deployctl deploy --project=my-project server/index.ts
 ```
 
-## Deploy within CI/CD using gitHub actions
+## Deploy within CI/CD using GitHub actions
 
 You just need to include the deployctl GitHub Action as a step in your workflow.