💡Add .sha256 checksum files for each asset

[shmick]

Describe the feature you'd like
For each asset in a release eg: cloudflared-linux-arm64 there should be an associated checksum file eg: cloudflared-linux-arm64.sha256 that contains the checksum. This would make the process of validating the checksums much easier instead of having to parse the body of the release eg curl -s https://api.github.com/repos/cloudflare/cloudflared/releases/tags/2025.2.0 | jq -r .body and then iterate through the list.

Simply downloading cloudflared-linux-arm64 and cloudflared-linux-arm64.sha256 and then comparing the output of shasum -256 cloudflared-linux-arm64 to the value inside of cloudflared-linux-arm64.sha256 would be a more straightforward process for doing this programatically.