Add possibility to choose between version v3 or v4 for the gitlab api.

Apart from the uri versioning, one big change is the snippet visibility post data (visibility_level -> visibility)

Default gitlab api version to v4

Signed-off-by: Cédric Couralet <cedric.couralet@gmail.com>

lib/config/index.js

@@ -103,6 +103,12 @@ config.isSAMLEnable = config.saml.idpSsoUrl
 config.isOAuth2Enable = config.oauth2.clientID && config.oauth2.clientSecret
 config.isPDFExportEnable = config.allowPDFExport
 
+// Check gitlab api version
+if (config.gitlab.version !== 'v4' || config.gitlab.version !== 'v3') {
+  logger.warn('config.js contains wrong version (' + config.gitlab.version + ') for gitlab api; it should be \'v3\' or \'v4\'. Defaulting to v3')
+  config.gitlab.version = 'v4'
+}
+
 // Only update i18n files in development setups
 config.updateI18nFiles = (env === Environment.development)