jwt token decode isn't urlsafe

[sillidev]

Hi,

I'm using this plugin to connect redmine & keycloak. Recently, I was informed an user cannot login redmine. After checking, the problem comes from the way we decode id_token

given this id_token eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJleHAiOjE1OTY1MzIyNDUsImlhdCI6MTU5NjUyMjk3OSwiYXV0aF90aW1lIjoxNTk2NTIyOTc5LCJqdGkiOiIwZmRlNzRjNS1lYzBiLTQyZDUtODlhNS0zMDI1YzE1OWQ4NjAiLCJpc3MiOiJodHRwczovL3Nzby10ZXN0LmxvY2FsL2F1dGgvcmVhbG1zL2RlbW8iLCJhdWQiOiJyZWRtaW5lIiwic3ViIjoiMjFjMWRiYzQtM2M3MC00YzM3LTlkMWMtODM1OTBhMjZiNWNmIiwidHlwIjoiSUQiLCJhenAiOiJyZWRtaW5lIiwibm9uY2UiOiIyZWJjMjhiYi1lNTMyLTQxYWEtYTBkNS0xMzE0Yzg5MjlkMDciLCJzZXNzaW9uX3N0YXRlIjoiYjI2MjYxNmItNGNhNS00OGZiLWFkY2ItOTY2YzNhNTQwYzg0IiwiYWNyIjoiMSIsImVtYWlsX3ZlcmlmaWVkIjpmYWxzZSwidXNlcl9uYW1lIjoibS5waGFtIiwibmFtZSI6IkPDqWRyaWMtSm_DqSBQT09UVEFSRU4iLCJwcmVmZXJyZWRfdXNlcm5hbWUiOiJtLnBoYW0iLCJnaXZlbl9uYW1lIjoiQ8OpZHJpYy1Kb8OpIiwibWVtYmVyX29mIjpbInVzZXIiXSwiZmFtaWx5X25hbWUiOiJQT09UVEFSRU4iLCJlbWFpbCI6Im0ucGhhbUBlbWFpbC5jb20ifQ.dRblJ7Nex4TBEQH6UNatVnNbUJYW6N122IOSMcee3SA

the output is
{"exp":1596532245,"iat":1596522979,"auth_time":1596522979,"jti":"0fde74c5-ec0b-42d5-89a5-3025c159d860","iss":"https://sso-test.local/auth/realms/demo","aud":"redmine","sub":"21c1dbc4-3c70-4c37-9d1c-83590a26b5cf","typ":"ID","azp":"redmine","nonce":"2ebc28bb-e532-41aa-a0d5-1314c8929d07","session_state":"b262616b-4ca5-48fb-adcb-966c3a540c84","acr":"1","email_verified":false,"user_name":"m.pham","name":"Cédric-J`�H������T�S����Y�\��Y��\�\��[YH���K���[H��]�[�ۘ[YH�����Y��X�R���H�Y[X�\��و��ȝ\�\����[Z[�Wۘ[YH��������T�S��[XZ���K���[P�[XZ[
���H�

which is not a valid json

I see we already have a PR for the fix #27 - can you help to review & merge it ?

Thanks