Release v0.28.0

In this release:

• a breaking change that will affect you if you used branch name variables in your ingress host names. See #28
  tldr: you have to sanitize ingress host names in your values files or in the scripts that generate them.
  If you are using Gimlet, sanitizeDNS name will do it:

app: myapp-{{ .GITHUB_BRANCH }}
env: preview
namespace: default
chart:
  repository: https://chart.onechart.dev
  name: onechart
  version: 0.28.0
values:
  ingress:
    host: myapp-{{ .GITHUB_BRANCH | sanitizeDNSName }}.mycompany.com