chore: update linter groupd ID to the latest

Follows from googleapis/java-shared-config#1003

Author: diegomarquezp

.kokoro/build.sh

@@ -62,7 +62,7 @@ test)
     RETURN_CODE=$?
     ;;
 lint)
-    mvn com.coveo:fmt-maven-plugin:check -B -ntp
+    mvn com.spotify.fmt:fmt-maven-plugin:check -B -ntp
     RETURN_CODE=$?
     ;;
 javadoc)