2.1.0-rc1

enhancement:

• update portainer to 2.20.1 #460
• portainer plugin update

bug:

• add credentials to apphub #458
• all app container exec error on portainer #464

appstore:

• complete docker-compose for [Graphite]
• add docker-compose for [gospeed]
• Can't find device management at console of [thingsboard]
• improve docker-compose for [screego]