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/grpc-ecosystem/grpc-gateway/runtime/marshaler_registry.go

@@ -2,7 +2,10 @@ package runtime
 
 import (
 	"errors"
+	"mime"
 	"net/http"
+
+	"google.golang.org/grpc/grpclog"
 )
 
 // MIMEWildcard is the fallback MIME type used for requests which do not match
@@ -31,7 +34,12 @@ func MarshalerForRequest(mux *ServeMux, r *http.Request) (inbound Marshaler, out
 	}
 
 	for _, contentTypeVal := range r.Header[contentTypeHeader] {
-		if m, ok := mux.marshalers.mimeMap[contentTypeVal]; ok {
+		contentType, _, err := mime.ParseMediaType(contentTypeVal)
+		if err != nil {
+			grpclog.Infof("Failed to parse Content-Type %s: %v", contentTypeVal, err)
+			continue
+		}
+		if m, ok := mux.marshalers.mimeMap[contentType]; ok {
 			inbound = m
 			break
 		}