Allow any user in Mattermost server write to anyone by DM (System console > Users and teams > Enable users to open Direct Message channels with > Any user on the Mattermost server). This is fixed in server v6.7.0
Go into the cloned directory and run make. You will need to upload this to your mattermost instance through the system console and provide it a Client secret and Client ID.
When building is finished, the plugin file is available at dist/com.github.lugamuga.mattermost-yandex-calendar-plugin-VERSION.tar.gz
main handles deployment of the plugin to a development server using either the Client4 API or by copying the plugin bundle into a sibling mattermost-server/plugin directory.
main handles deployment of the plugin to a development server using either the Client4 API or by copying the plugin bundle into a sibling mattermost-server/plugin directory.