ingress-nginx-app release v1.6.8

Default max-worker-connections to 0, making it same as max-worker-open-files i.e. max open files (system's limit) / worker-processes - 1024. This optimizes for high load conditions where it improves performance at the cost of increasing RAM utilization (even on idle).
HorizontalPodAutoscaler was tuned to use targetMemoryUtilizationPercentage of 80 due to increased RAM utilization with new default for max-worker-connections of 0.
Removed use of enable-dynamic-certificates CLI flag, it has been deprecated since ingress-nginx 0.26.0 via ingress-nginx PR #4356
Changed default error-log-level from error to notice.
Added a link to the README in the sources of Chart.yaml