add missing alt text.

Author: nisarhassan12

src/contents/gitpod-vs-codespaces.tsx

@@ -59,6 +59,7 @@ export const features: FeatureCardProps[] = [
         </ul>
       </>
     ),
-    src: GitPlatforms
+    src: GitPlatforms,
+    alt: 'Git Platforms'
   }
 ]

src/contents/index.tsx

@@ -36,6 +36,7 @@ export const features: FeatureCardProps[] = [
   {
     id: 'teams-together',
     src: Collaboration,
+    alt: 'A code review within Gitpod',
     title: (
       <strong>
         Where Teams