Avoid time.Compare

It looks like the github action build environment for this repo uses
a go 1.19.x environment which does not have time.Compare(). Replace
with time.Before() and time.After() instead.

(cherry picked from commit a579ea8)
(cherry picked from commit ffd8a2d)
(cherry picked from commit 24eaaf5)
(cherry picked from commit 6020e24)

billing_test.go

@@ -56,11 +56,11 @@ func TestBillingUsageSessKey(t *testing.T) {
 			resp.TotalUsage)
 	}
 	for idx, dc := range resp.DailyCosts {
-		if dc.Time.Compare(startDate) < 0 {
+		if dc.Time.Before(startDate) {
 			t.Errorf("expected daily cost%v date(%v) before start date %v", idx,
 				dc.Time, TestStartDate)
 		}
-		if dc.Time.Compare(endDate) > 0 {
+		if dc.Time.After(endDate) {
 			t.Errorf("expected daily cost%v date(%v) after end date %v", idx,
 				dc.Time, TestEndDate)
 		}