agvtool Not Found

Running fastlane in Pipelines, and fastlane's get_version_number uses Apple's agvtool to get the current version # from iTunes Connect.

It's failing because it cannot find agvtool on the Pipeline machines.

I get this error:

Exit status of command 'cd /opt/atlassian/pipelines/agent/build && agvtool what-marketing-version -terse' was 127 instead of 0.
sh: 1: agvtool: not found

How do I make sure this is added? I've already included gem "xcode-install" in my gemfile.

Gemfile:

source "https://rubygems.org"

gem "fastlane"
gem "cocoapods"
gem "badge"
gem "xcode-install"