[chart/redis-ha][REQUEST] change default image tag for haproxy to alpine build image

[martijnvdp]

Is your feature request related to a problem? Please describe. is there a reason to stick with the non alpine image for ha-proxy ? cant this also be the alpine release image like redis?

Describe the solution you'd like change default image tag for haproxy to 2.6.9-alpine

Additional context The alpine image seem to have less security issues