[REFACTOR] don't use slices since not supported

Error: pkg/handler/unrouted_handler.go:12:2: package slices is not in GOROOT (/Users/runner/hostedtoolcache/go/1.20.12/x64/src/slices)

pkg/handler/unrouted_handler.go

@@ -9,7 +9,6 @@ import (
 	"mime"
 	"net/http"
 	"regexp"
-	"slices"
 	"strconv"
 	"strings"
 	"time"
@@ -26,10 +25,6 @@ const (
 	Version4 DraftVersion = "4"
 )
 
-var (
-	supportedUploadDraftInteropVersions = []DraftVersion{Version3, Version4}
-)
-
 var (
 	reExtractFileID  = regexp.MustCompile(`([^/]+)\/?$`)
 	reForwardedHost  = regexp.MustCompile(`host="?([^;"]+)`)
@@ -1372,7 +1367,7 @@ func (handler *UnroutedHandler) lockUpload(c *httpContext, id string) (Lock, err
 // related to resumable upload draft from IETF (instead of tus v1)
 func (handler UnroutedHandler) isResumableUploadDraftRequest(r *http.Request) bool {
 	interopVersionHeader := handler.getResumeableUploadDraftVersion(r)
-	supportedInteropVersion := slices.Contains(supportedUploadDraftInteropVersions, interopVersionHeader)
+	supportedInteropVersion := interopVersionHeader == Version3 || interopVersionHeader == Version4
 	return handler.config.EnableExperimentalProtocol && supportedInteropVersion
 }