update all vendored dependencies

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

@@ -10,7 +10,6 @@ import (
 	"bufio"
 	"bytes"
 	"errors"
-	"fmt"
 	"io"
 	"io/ioutil"
 	"net/http"
@@ -41,7 +40,11 @@ type Cache interface {
 
 // cacheKey returns the cache key for req.
 func cacheKey(req *http.Request) string {
-	return req.URL.String()
+	if req.Method == http.MethodGet {
+		return req.URL.String()
+	} else {
+		return req.Method + " " + req.URL.String()
+	}
 }
 
 // CachedResponse returns the cached http.Response for req if present, and nil
@@ -189,16 +192,11 @@ 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 {