chore: add Gradle as Scala Center supporters

Author: hamzaremmal

_data/scala-supporters.yml

@@ -6,6 +6,10 @@ supporters:
     logo: /resources/img/frontpage/jetbrains-logo.png
     url: https://www.jetbrains.com/
     wider-logo: true
+  - name: Gradle
+    logo: /resources/img/frontpage/gradle-logo.png
+    url: https://www.gradle.com/
+    wider-logo: true
   - name: Your company
     logo: /resources/img/frontpage/company-logo.png
     url: https://scala.epfl.ch/corporate-membership.html