feat/catalog-backend-module-gitlab: create url location only if file exists (fixes #2)

Signed-off-by: Ruslan.Nasyrov <goququ@ya.ru>

docs/integrations/gitlab/discovery.md

@@ -47,6 +47,9 @@ of your backend.
  ): Promise<Router> {
    const builder = await CatalogBuilder.create(env);
 +  builder.addProcessor(
-+    GitLabDiscoveryProcessor.fromConfig(env.config, { logger: env.logger })
++    GitLabDiscoveryProcessor.fromConfig(env.config, {
++       logger: env.logger,
++       skipReposWithoutExactFileMatch: true,
++    })
 +  );
 ```