Add CNAME record charts.jenkins.io
Add CNAME record charts.jenkins.io

As suggested by @timja in https://github.com/jenkinsci/helm-charts/pull/1#discussion_r477222318
this adds a CNAME record which points to helm charts

Signed-off-by: Torsten Walter <1d6e1cf70ec6f9ab28d3ea4b27a49a77654d370e@torstenwalter.de>

olblak/azure,olblak/azure,jenkins-infra/azure,olblak/azure