RFR: 1803: GitLabRepository.canPush only checks direct members

[Erik Joelsson]

The method `canPush` on GitLabRepository uses the wrong endpoint for the query. It only checks for direct members and not inherited members (https://docs.gitlab.com/ee/api/members.html).

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Commit messages:
 - SKARA-1803

Changes: https://git.openjdk.org/skara/pull/1462/files
 Webrev: https://webrevs.openjdk.org/?repo=skara&pr=1462&range=00
  Issue: https://bugs.openjdk.org/browse/SKARA-1803
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/skara/pull/1462.diff
  Fetch: git fetch https://git.openjdk.org/skara pull/1462/head:pull/1462

PR: https://git.openjdk.org/skara/pull/1462