Build failed - Webmock 3.16.0 no longer available

Hiya,

Just attempted a first time install but it's failing due to webmock 3.16.0 no longer being available. It's been yanked from rubygems for some reason.

_Your bundle is locked to webmock (3.16.0) from rubygems repository
https://rubygems.org/ or installed locally, but that version can no longer be
found in that source. That means the author of webmock (3.16.0) has removed it.
You'll need to update your bundle to a version other than webmock (3.16.0) that
hasn't been removed in order to install._

_The command '/bin/sh -c apk add --no-cache build-base git ruby-dev ruby-etc ruby-io-console ruby-json libxml2-dev vips-dev && git clone https://github.com/feedbin/image.git /app && gem install bundler && bundle install' returned a non-zero code: 7
ERROR: Service 'feedbin-image' failed to build : Build failed_

Thanks