Looks like :function_groups was removed in ExDoc v0.29.1. Specifying an older version explicitly seems to work:
Mix.install([
{:ex_doc, "0.29.0"},
{:zigler, "~> 0.9.1"}
])
Looks like :function_groups was removed in ExDoc v0.29.1. Specifying an older version explicitly seems to work:
Mix.install([
{:ex_doc, "0.29.0"},
{:zigler, "~> 0.9.1"}
])