[Vendor] Update go-redis to v8.5.0 (#13749)

* Update go-redis to v8.4.0

* github.com/go-redis/redis/v8  v8.4.0 -> v8.5.0

* Apply suggestions from code review

Co-authored-by: zeripath <art27@cantab.net>

* TODO

* Use the Queue termination channel as the default context for pushes

Signed-off-by: Andrew Thornton <art27@cantab.net>

* missed one

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: zeripath <art27@cantab.net>

vendor/go.opentelemetry.io/otel/handler.go

@@ -0,0 +1,89 @@
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package otel // import "go.opentelemetry.io/otel"
+
+import (
+	"log"
+	"os"
+	"sync"
+	"sync/atomic"
+)
+
+var (
+	// globalErrorHandler provides an ErrorHandler that can be used
+	// throughout an OpenTelemetry instrumented project. When a user
+	// specified ErrorHandler is registered (`SetErrorHandler`) all calls to
+	// `Handle` and will be delegated to the registered ErrorHandler.
+	globalErrorHandler = &loggingErrorHandler{
+		l: log.New(os.Stderr, "", log.LstdFlags),
+	}
+
+	// delegateErrorHandlerOnce ensures that a user provided ErrorHandler is
+	// only ever registered once.
+	delegateErrorHandlerOnce sync.Once
+
+	// Comiple time check that loggingErrorHandler implements ErrorHandler.
+	_ ErrorHandler = (*loggingErrorHandler)(nil)
+)
+
+// loggingErrorHandler logs all errors to STDERR.
+type loggingErrorHandler struct {
+	delegate atomic.Value
+
+	l *log.Logger
+}
+
+// setDelegate sets the ErrorHandler delegate if one is not already set.
+func (h *loggingErrorHandler) setDelegate(d ErrorHandler) {
+	if h.delegate.Load() != nil {
+		// Delegate already registered
+		return
+	}
+	h.delegate.Store(d)
+}
+
+// Handle implements ErrorHandler.
+func (h *loggingErrorHandler) Handle(err error) {
+	if d := h.delegate.Load(); d != nil {
+		d.(ErrorHandler).Handle(err)
+		return
+	}
+	h.l.Print(err)
+}
+
+// GetErrorHandler returns the global ErrorHandler instance. If no ErrorHandler
+// instance has been set (`SetErrorHandler`), the default ErrorHandler which
+// logs errors to STDERR is returned.
+func GetErrorHandler() ErrorHandler {
+	return globalErrorHandler
+}
+
+// SetErrorHandler sets the global ErrorHandler to be h.
+func SetErrorHandler(h ErrorHandler) {
+	delegateErrorHandlerOnce.Do(func() {
+		current := GetErrorHandler()
+		if current == h {
+			return
+		}
+		if internalHandler, ok := current.(*loggingErrorHandler); ok {
+			internalHandler.setDelegate(h)
+		}
+	})
+}
+
+// Handle is a convience function for ErrorHandler().Handle(err)
+func Handle(err error) {
+	GetErrorHandler().Handle(err)
+}