Update protobuf,grpc,etcd dependencies

1. Updated etcd/protobuf/grpc dependencies:

echo "
hack/pin-dependency.sh github.com/golang/protobuf latest
hack/pin-dependency.sh google.golang.org/protobuf latest
hack/pin-dependency.sh go.etcd.io/etcd/api/v3 v3.5.0-rc.0
hack/pin-dependency.sh go.etcd.io/etcd/client/v3 v3.5.0-rc.0
hack/pin-dependency.sh go.etcd.io/etcd/client/pkg/v3 v3.5.0-rc.0
hack/pin-dependency.sh go.etcd.io/etcd/pkg/v3 v3.5.0-rc.0
hack/pin-dependency.sh go.etcd.io/etcd/server/v3 v3.5.0-rc.0
hack/pin-dependency.sh go.etcd.io/etcd/tests/v3 v3.5.0-rc.0
hack/pin-dependency.sh google.golang.org/grpc latest
" | bash

2. Linted transitive dependencies until versions are clean:

hack/lint-dependencies.sh  | grep "  hack/pin-dependency.sh" | bash

3. Linted dependencies until dropped versions are clean:

hack/lint-dependencies.sh  | grep "dropreplace" | bash

4. Updated vendor and internal modules:

hack/update-vendor.sh
hack/update-internal-modules.sh

Repeated steps 2-4 until clean

vendor/github.com/jonboulle/clockwork/ticker.go

@@ -0,0 +1,72 @@
+package clockwork
+
+import (
+	"time"
+)
+
+// Ticker provides an interface which can be used instead of directly
+// using the ticker within the time module. The real-time ticker t
+// provides ticks through t.C which becomes now t.Chan() to make
+// this channel requirement definable in this interface.
+type Ticker interface {
+	Chan() <-chan time.Time
+	Stop()
+}
+
+type realTicker struct{ *time.Ticker }
+
+func (rt *realTicker) Chan() <-chan time.Time {
+	return rt.C
+}
+
+type fakeTicker struct {
+	c      chan time.Time
+	stop   chan bool
+	clock  FakeClock
+	period time.Duration
+}
+
+func (ft *fakeTicker) Chan() <-chan time.Time {
+	return ft.c
+}
+
+func (ft *fakeTicker) Stop() {
+	ft.stop <- true
+}
+
+// runTickThread initializes a background goroutine to send the tick time to the ticker channel
+// after every period. Tick events are discarded if the underlying ticker channel does not have
+// enough capacity.
+func (ft *fakeTicker) runTickThread() {
+	nextTick := ft.clock.Now().Add(ft.period)
+	next := ft.clock.After(ft.period)
+	go func() {
+		for {
+			select {
+			case <-ft.stop:
+				return
+			case <-next:
+				// We send the time that the tick was supposed to occur at.
+				tick := nextTick
+				// Before sending the tick, we'll compute the next tick time and star the clock.After call.
+				now := ft.clock.Now()
+				// First, figure out how many periods there have been between "now" and the time we were
+				// supposed to have trigged, then advance over all of those.
+				skipTicks := (now.Sub(tick) + ft.period - 1) / ft.period
+				nextTick = nextTick.Add(skipTicks * ft.period)
+				// Now, keep advancing until we are past now. This should happen at most once.
+				for !nextTick.After(now) {
+					nextTick = nextTick.Add(ft.period)
+				}
+				// Figure out how long between now and the next scheduled tick, then wait that long.
+				remaining := nextTick.Sub(now)
+				next = ft.clock.After(remaining)
+				// Finally, we can actually send the tick.
+				select {
+				case ft.c <- tick:
+				default:
+				}
+			}
+		}
+	}()
+}