envoy: Allow use of architecture-specific Envoy images for testing
envoy: Allow use of architecture-specific Envoy images for testing

Detect hyphen `-` as the end of the commit/version SHA in Envoy image
tags. This allows the use of architecture-specific tags, such as
"1234567890abcdef-arm64". This is only useful for testing on a specific
architecture, as this drops support for the excluded architecture.

Signed-off-by: Jarno Rajahalme <0f1ab0ac7dffd9db21aa539af2fd4bb04abc3ad4@isovalent.com>

cilium/cilium,cilium/cilium,cilium/cilium,cilium/cilium,cilium/cilium