securityContext example misleading / port 80 hardcoded

[abh]

the securityContext section in the default values.yaml implies that dropping all capabilities and running as non-root is possible; however this quickly fails because the chart seemingly is hardcoded to have drone listen on port 80.

[jimsheldon]

Apologies for the delay on this. Let's continue the discussion on this in #37

[abh]

Thank you for picking it up, @jimsheldon :-)