🎉 Source Gitlab: add OAuth2.0 authentication support (#7506)

* added support of oauth2.0

* added OAuthFlow.java part

* bumped version of the Dockerfile

* corrected SAT

* added unit_test for Oauth java part, added integration-test for java part

* added changelog

* fix java part test

* updated after review

* updated spec.json

* updated after review

* #7480 source gitlab: rm empty files

* #7480 source gitlab: add single use refresh token authenticator

* #7480 source gitlab: upd oauth implementation

* #7480 source gitlab: refactor auth

* #7480 fix oauth: java

* #7480 source gitlab: review fixes

* #7480 source gitlab: upd release stage

* #7480 source gitlab: fix unit tests

* #7480 source gitlab: update expected records

* #7480 source gitlab: upd sats

* #7480 source gitlab: upd expected records

* #7480 source Gitlab: use SingleUseRefreshTokenOauth as is

* #7480 sourcte gitlab: upd expected records

* auto-bump connector version

Co-authored-by: Denys Davydov <davydov.den18@gmail.com>
Co-authored-by: Augustin <augustin@airbyte.io>
Co-authored-by: Octavia Squidington III <octavia-squidington-iii@users.noreply.github.com>

airbyte-integrations/connectors/source-gitlab/unit_tests/conftest.py

@@ -10,5 +10,8 @@ def config(mocker):
     return {
         "start_date": "2021-01-01T00:00:00Z",
         "api_url": "gitlab.com",
-        "private_token": "secret_token"
+        "credentials": {
+            "auth_type": "access_token",
+            "access_token": "token"
+        }
     }