`tini` binary sourced in Dockerfile is not architecture-specific

tini is added directly to the Docker image at build time by URL reference: https://github.com/vexxhost/docker-openvswitch/blob/main/Dockerfile#L88

However, that URL is not architecture-specific, and seems to point to the amd64 release as a default. The result is that arm64-architecture container images are built and can be pulled and run on arm64 nodes, but the invocation of tini fails with:

openvswitch-vswitchd exec /tini: exec format error

There are amd64 and arm64 release variants available in the tini releases repo. Specifying $TARGETARCH as a component of the url (eg https://github.com/krallin/tini/releases/download/v0.19.0/tini-${TARGETARCH}) should suffice to build a working container image for both amd64 and arm64, along with any other architectures that this image is built for that are also built for by tini.

Inspect Dockerfile line 88 and the surrounding image-build arguments first. Compare the current fixed tini URL with the architecture-specific release variants and verify builds for amd64 and arm64. Done means the resulting images can invoke /tini successfully on their corresponding architectures without an exec format error.