Fixes

• Use helm3 for the airgap example #1759
• Properly format numbers parsed from jsonPath outputs #1755
• Update helm3 mixin doc #1749
• Update CI to build on the latest ubuntu LTS
• chore(examples/azure-terraform): updates per forthcoming 0.8.0 release

Install or Upgrade

Run (or re-run) the installation from https://porter.sh/install to get the latest version of porter.