Publish release archives with normalized OS and Arch names

[tgoodsell-tempus]

For example: https://github.com/google/go-jsonnet/releases/download/v0.21.0/go-jsonnet_Linux_x86_64.tar.gz

The OS is "Linux" in this URL, while the arch name is "x86_64". This means something like: curl --silent --location --output "/tmp/go-jsonnet_0.21.0_${TARGETOS}_${TARGETARCH}.tar.gz" https://nexus.opstempus.com/repository/github-proxy/google/go-jsonnet/releases/download/v0.21.0/go-jsonnet_0.21.0_${TARGETOS}_${TARGETARCH}.tar.gz" won't work in a Dockerfile.

I know I can swap these out for $(uname -s) and $(uname -m) respectively, however, these other styles are generally the Golang convention and are found fairly often as the labels for other go generated artifacts.

I myself haven't found any RFCs or anything which constitutes the "consensus choice" on these naming conventions. So my hope here is you would start publishing as go-jsonnet_linux_amd64.tar.gz IN addition to the existing scheme, provided additional cost wasn't impactful.

[tgoodsell-tempus]

I'm also wrong about $(uname -m) much of the time, since this resolves to aarch64 on Mac OS (where we'd expect to find the users of https://github.com/google/go-jsonnet/releases/download/v0.21.0/go-jsonnet_Darwin_arm64.tar.gz)