Update go.mod and vendor

vendor/github.com/moby/buildkit/util/throttle/throttle.go

@@ -1,58 +0,0 @@
-package throttle
-
-import (
-	"sync"
-	"time"
-)
-
-// Throttle wraps a function so that internal function does not get called
-// more frequently than the specified duration.
-func Throttle(d time.Duration, f func()) func() {
-	return throttle(d, f, true)
-}
-
-// ThrottleAfter wraps a function so that internal function does not get called
-// more frequently than the specified duration. The delay is added after function
-// has been called.
-func ThrottleAfter(d time.Duration, f func()) func() {
-	return throttle(d, f, false)
-}
-
-func throttle(d time.Duration, f func(), wait bool) func() {
-	var next, running bool
-	var mu sync.Mutex
-	return func() {
-		mu.Lock()
-		defer mu.Unlock()
-
-		next = true
-		if !running {
-			running = true
-			go func() {
-				for {
-					mu.Lock()
-					if next == false {
-						running = false
-						mu.Unlock()
-						return
-					}
-					if !wait {
-						next = false
-					}
-					mu.Unlock()
-
-					if wait {
-						time.Sleep(d)
-						mu.Lock()
-						next = false
-						mu.Unlock()
-						f()
-					} else {
-						f()
-						time.Sleep(d)
-					}
-				}
-			}()
-		}
-	}
-}