Add default event filter (#1140)

breakout from #934

when new events are added you don't have to worry that pipeline will behave different as it does now with this

Co-authored-by: Anbraten <anton@ju60.de>

server/shared/procBuilder_test.go

@@ -465,7 +465,9 @@ depends_on: [ shouldbefiltered ]
 func TestTree(t *testing.T) {
 	t.Parallel()
 
-	build := &model.Build{}
+	build := &model.Build{
+		Event: model.EventPush,
+	}
 
 	b := ProcBuilder{
 		Repo:  &model.Repo{},