Update urls and add missing

Update group_access_tokens.go and add enum in types.go

This MR updates the group access tokens implementation to better match the GitLab API.

Changes

• Added missing filters in group_access_tokens.go:
  • expires_after
  • expires_before
  • sort
• Added a new enum AccessTokenSort in types.go to represent valid sorting values.

Reference

Missing query parameters for Group Access Tokens (#2234) · Issue · gitlab-org/api/client-go