[Perl] Generating fails with exception

Created by: ta2-1

openapi-generator 3.1.2 installed via Homebrew fails on https://gist.github.com/ta2-1/19600dae5c611a8e7dbcdd248a41d470#file-smartcat-json. It's regression comparing to swagger-codegen 2.3.1.

openapi-generator generate \
-i ./smartcat.json \
-g perl \
-c ./smartcat.config \
-o /path/to/lib \
--git-user-id ta2-1 \
--git-repo-id smartcat-api-perl \
--release-note "Create Smartcat Perl API library generated by openapi-generator"

See https://gist.github.com/ta2-1/19600dae5c611a8e7dbcdd248a41d470#file-generate-error for STDERR output.