fix(plugins/followup): fallback to owner if collaborators are not accessible (relates #859)

source/plugins/followup/README.md

@@ -77,6 +77,8 @@ The `plugin_followup_indepth` option collects additional stats to differentiate
 
 It helps knowing whether repositories are also maintained by other users and give an overall health status of repositories.
 
+> ⚠️ This mode will try to list users with push access to know who are the maintainers in order to place issues in the correct category, which requires a `repo` scope. If not available, it will consider that only the owner is a maintainer.
+
 ## ℹ️ Examples workflows
 
 <!--examples-->

source/plugins/followup/index.mjs

@@ -67,7 +67,7 @@ export default async function({login, data, computed, imports, q, graphql, queri
             console.debug(`metrics/compute/${login}/plugins > followup > processing ${owner}/${repo}`)
             followup.indepth.repositories[`${owner}/${repo}`] = {stats:{}}
             //Fetch users with push access
-            let {repository:{collaborators:{nodes:collaborators}}} = await graphql(queries.followup["repository.collaborators"]({repo, owner}))
+            let {repository:{collaborators:{nodes:collaborators}}} = await graphql(queries.followup["repository.collaborators"]({repo, owner})).catch(() => ({repository:{collaborators:{nodes:[{login:owner}]}}}))
             console.debug(`metrics/compute/${login}/plugins > followup > found ${collaborators.length} collaborators`)
             followup.indepth.repositories[`${owner}/${repo}`].collaborators = collaborators.map(({login}) => login)
             //Fetch issues and pull requests created by collaborators