go.mod: bump github.com/studio-b12/gowebdav

For https://github.com/studio-b12/gowebdav/pull/87

Fixes #20295

Change-Id: I8ae6ff6969c84fcd510f0e15e0487fbfe9f7c821
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

drive/driveimpl/drive_test.go

@@ -522,7 +522,7 @@ func newSystem(t *testing.T) *system {
 		}
 	}()
 
-	client := gowebdav.NewAuthClient(fmt.Sprintf("http://%s", ln.Addr()), &noopAuthorizer{})
+	client := gowebdav.NewClient(fmt.Sprintf("http://%s", ln.Addr()), "", "")
 	client.SetTransport(&http.Transport{DisableKeepAlives: true})
 	s := &system{
 		t:     t,
@@ -772,36 +772,6 @@ func pathTo(remote, share, name string) string {
 	return path.Join(domain, remote, share, name)
 }
 
-// noopAuthorizer implements gowebdav.Authorizer. It does no actual
-// authorizing. We use it in place of gowebdav's built-in authorizer in order
-// to avoid a race condition in that authorizer.
-type noopAuthorizer struct{}
-
-func (a *noopAuthorizer) NewAuthenticator(body io.Reader) (gowebdav.Authenticator, io.Reader) {
-	return &noopAuthenticator{}, nil
-}
-
-func (a *noopAuthorizer) AddAuthenticator(key string, fn gowebdav.AuthFactory) {
-}
-
-type noopAuthenticator struct{}
-
-func (a *noopAuthenticator) Authorize(c *http.Client, rq *http.Request, path string) error {
-	return nil
-}
-
-func (a *noopAuthenticator) Verify(c *http.Client, rs *http.Response, path string) (redo bool, err error) {
-	return false, nil
-}
-
-func (a *noopAuthenticator) Clone() gowebdav.Authenticator {
-	return &noopAuthenticator{}
-}
-
-func (a *noopAuthenticator) Close() error {
-	return nil
-}
-
 const lockBody = `<?xml version="1.0" encoding="utf-8" ?>
 <D:lockinfo xmlns:D='DAV:'>
   <D:lockscope><D:exclusive/></D:lockscope>