Running datasource plugin on grafana 8.0.4 fails

We have a datasource plugin, which is perfectly running with grafana 7.5.8+.
But when I launch it with grafana 8.0.4 it fails. Any ideas why is this happening?

Plugin in GitHub

docker-compose:

version: '2'
services:
  grafana8:
    user: root
    image: grafana/grafana:8.0.4
    ports:
      - "3001:3000"
    environment: 
      - GF_PLUGINS_ALLOW_LOADING_UNSIGNED_PLUGINS=epam-timebase-datasource
      - GF_PLUGINS_PLUGIN_ADMIN_ENABLED=true
      - GF_INSTALL_PLUGINS=https://github.com/epam/TimeBaseGrafanaPlugin/releases/download/1.0.5/epam-timebase-datasource.zip;epam-timebase-datasource
    volumes:
      - grafana-volume:/var/lib/grafana
      - ./datasources8:/etc/grafana/provisioning/datasources  # provisioning datasources directory

volumes:
  grafana8-volume:

screenshot: