[maintenance] in demo, use ${project.version} for the plugin, instead of fixed 6.0.0
[maintenance] in demo, use ${project.version} for the plugin, instead of fixed 6.0.0

onehippo-forge/external-document-picker,onehippo-forge/external-document-picker,onehippo-forge/external-document-picker,onehippo-forge/external-document-picker