Add support for custom environments in GitLab integration

frontend/src/components/integrations/Integration.tsx

@@ -191,6 +191,17 @@ const IntegrationTile = ({
               />
             </div>
           );
+        case 'gitlab':
+          return (
+            <div>
+              <div className="mb-2 text-xs font-semibold text-gray-400">ENVIRONMENT</div>
+              <ListBox
+                data={null}
+                isSelected={integration.targetEnvironment}
+                onChange={setIntegrationTargetEnvironment}
+              />
+            </div>
+          );
         default:
           return <div />;
       }