I would use env variable GF_INSTALL_PLUGINS on the container level, you can define plugin version explicitly there, e.g.
GF_INSTALL_PLUGINS=grafana-dynatrace-datasource 0.9.5,grafana-splunk-datasource 3.0.1,grafana-servicenow-datasource 2.2.6
Of course also cli has support for plugin version.
grafana cli plugins install <plugin-id> <version>