Update go dependencies (#4322)

vendor/github.com/gregjones/httpcache/httpcache.go

@@ -10,6 +10,7 @@ import (
 	"bufio"
 	"bytes"
 	"errors"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"net/http"
@@ -40,11 +41,7 @@ type Cache interface {
 
 // cacheKey returns the cache key for req.
 func cacheKey(req *http.Request) string {
-	if req.Method == http.MethodGet {
-		return req.URL.String()
-	} else {
-		return req.Method + " " + req.URL.String()
-	}
+	return req.URL.String()
 }
 
 // CachedResponse returns the cached http.Response for req if present, and nil
@@ -192,11 +189,16 @@ func (t *Transport) RoundTrip(req *http.Request) (resp *http.Response, err error
 			for _, header := range endToEndHeaders {
 				cachedResp.Header[header] = resp.Header[header]
 			}
+			cachedResp.Status = fmt.Sprintf("%d %s", http.StatusOK, http.StatusText(http.StatusOK))
+			cachedResp.StatusCode = http.StatusOK
+
 			resp = cachedResp
 		} else if (err != nil || (cachedResp != nil && resp.StatusCode >= 500)) &&
 			req.Method == "GET" && canStaleOnError(cachedResp.Header, req.Header) {
 			// In case of transport failure and stale-if-error activated, returns cached content
 			// when available
+			cachedResp.Status = fmt.Sprintf("%d %s", http.StatusOK, http.StatusText(http.StatusOK))
+			cachedResp.StatusCode = http.StatusOK
 			return cachedResp, nil
 		} else {
 			if err != nil || resp.StatusCode != http.StatusOK {