http_archive fails after update

At one point, we fetch the a [binary](http://api.anaconda.org/download/conda-forge/micromamba/1.4.2/linux-64/micromamba-1.4.2-0.tar.bz2 ) as part of the build. This was working great, but now that request fails after an update of buck2. The binary is still available, the step just fails with a somewhat opaque:

```
Internal error: Error performing a http_head request: HTTP Client Error (404 Not Found) when querying URL: https://api.anaconda.org/download/conda-forge/micromamba/1.4.2/linux-64/micromamba-1.4.2-0.tar.bz2. Response text:
```

`cce725666b` works fine, current HEAD does not.