fix: Use correct casing for GitHub

This commit leaves the casing for blog post titles in the NixOS weekly
newletters untouched since those titles refer to posts in the wild that
use the incorrect casing.

Signed-off-by: squat <[email protected]>

Author: squat

core/src/pages/community.astro

@@ -108,10 +108,10 @@ const platformsMain = [
   },
   {
     href: 'https://github.com/NixOS/',
-    name: 'Github',
+    name: 'GitHub',
     iconName: 'simple-icons:github',
     description:
-      'Official organization page on Github, where you can find nix, nixpkgs, and other repositories.',
+      'Official organization page on GitHub, where you can find nix, nixpkgs, and other repositories.',
   },
 ];