add riscv release packages

### Description of the feature request:

With RISC-V becoming ever more popular, can we add risc-v prebuilt binaries for download?

I'm happy to do the leg work if someone could kindly point out the rough path for making it happen. It seems the current git repo assumes a bootstrap bazel package, which is a chicken'n'egg issue for risc-v.

### Which category does this issue belong to?

_No response_

### What underlying problem are you trying to solve with this feature?

Make bazel more friendly for RISC-V

### Which operating system are you running Bazel on?

_No response_

### What is the output of `bazel info release`?

_No response_

### If `bazel info release` returns `development version` or `(@non-git)`, tell us how you built Bazel.

_No response_

### What's the output of `git remote get-url origin; git rev-parse HEAD` ?

```text

```

### Have you found anything relevant by searching the web?

_No response_

### Any other information, logs, or outputs that you want to share?

_No response_

No files or tests are named. Start by examining the repository's bootstrap Bazel package and release packaging process, with attention to the stated chicken-and-egg issue for RISC-V. Done means there is a documented path and working prebuilt RISC-V binaries available for download.

Written by the indexing model from the issue text.