TUN-3375: Upgrade coredns and prometheus dependencies

vendor/google.golang.org/appengine/internal/api.go

@@ -58,8 +58,11 @@ var (
 
 	apiHTTPClient = &http.Client{
 		Transport: &http.Transport{
-			Proxy: http.ProxyFromEnvironment,
-			Dial:  limitDial,
+			Proxy:               http.ProxyFromEnvironment,
+			Dial:                limitDial,
+			MaxIdleConns:        1000,
+			MaxIdleConnsPerHost: 10000,
+			IdleConnTimeout:     90 * time.Second,
 		},
 	}
 

vendor/google.golang.org/appengine/internal/net.go

@@ -32,7 +32,7 @@ func limitDial(network, addr string) (net.Conn, error) {
 
 	// Dial with a timeout in case the API host is MIA.
 	// The connection should normally be very fast.
-	conn, err := net.DialTimeout(network, addr, 500*time.Millisecond)
+	conn, err := net.DialTimeout(network, addr, 10*time.Second)
 	if err != nil {
 		limitRelease()
 		return nil, err