I tested the module with nunjucks@2.3.0 and it works fine, I think it's time to update to new nunjucks.
I suggest using dynamic dependency definition for the latest version so you don't have to manually change it unless it's broken (there will be issues for that).
I tested the module with
nunjucks@2.3.0
and it works fine, I think it's time to update to new nunjucks.