haproxy update to 1.19.3-bb.0

Package Merge Request

Package Changes

• Updated chart version 1.12.0 -> 1.19.3
• Updated HAProxy v2.2.21 -> v2.2.31
• Added a DEVELOPMENT_MAINTENANCE.md

Package MR

big-bang/product/packages/haproxy!20 (merged)

For Issue

Closes big-bang/product/packages/haproxy#9 (closed)