backend: fs implements the Shutdowner interface

Since `tokenRenewer` adds a Shutdown method, we should call it to
clean up resources.

changes backends:
onedrive,box,pcloud,amazonclouddrive,hidrive,jottacloud,sharefile
,premiumizeme

Signed-off-by: rkonfj <rkonfj@gmail.com>

backend/onedrive/onedrive.go

@@ -1377,6 +1377,12 @@ func (f *Fs) ListR(ctx context.Context, dir string, callback fs.ListRCallback) (
 
 }
 
+// Shutdown shutdown the fs
+func (f *Fs) Shutdown(ctx context.Context) error {
+	f.tokenRenewer.Shutdown()
+	return nil
+}
+
 // Creates from the parameters passed in a half finished Object which
 // must have setMetaData called on it
 //
@@ -2755,6 +2761,7 @@ var (
 	_ fs.PublicLinker    = (*Fs)(nil)
 	_ fs.CleanUpper      = (*Fs)(nil)
 	_ fs.ListRer         = (*Fs)(nil)
+	_ fs.Shutdowner      = (*Fs)(nil)
 	_ fs.Object          = (*Object)(nil)
 	_ fs.MimeTyper       = &Object{}
 	_ fs.IDer            = &Object{}