fix: report GA event with value to indicate failure

internal/ga/client_test.go

@@ -8,7 +8,7 @@ func TestSendEvents(t *testing.T) {
 	event := EventTracking{
 		Category: "unittest",
 		Action:   "SendEvents",
-		Value:    "123",
+		Value:    123,
 	}
 	err := gaClient.SendEvent(event)
 	if err != nil {
@@ -21,7 +21,7 @@ func TestStructToUrlValues(t *testing.T) {
 		Category: "unittest",
 		Action:   "convert",
 		Label:    "v0.3.0",
-		Value:    "123",
+		Value:    123,
 	}
 	val := structToUrlValues(event)
 	if val.Encode() != "ea=convert&ec=unittest&el=v0.3.0&ev=123" {

internal/ga/events.go

@@ -17,7 +17,7 @@ type EventTracking struct {
 	Category string `form:"ec"` // Required. Event Category.
 	Action   string `form:"ea"` // Required. Event Action.
 	Label    string `form:"el"` // Optional. Event label, used as version.
-	Value    string `form:"ev"` // Optional. Event value, must be digits, "123"
+	Value    int    `form:"ev"` // Optional. Event value, must be non-negative integer
 }
 
 func (e EventTracking) StartTiming(variable string) UserTimingTracking {