Format the package hash files to include the package hash and filename
separated by two spaces, ensuring compatibility with the `sha256sum -c`
and `shasum -c` command.
---
Before:
```
╰─❯ sha256sum -c servo-latest.tar.gz.sha256
sha256sum: servo-latest.tar.gz.sha256: no properly formatted checksum lines found
```
After:
```
╰─❯ sha256sum -c servo-latest.tar.gz.sha256
servo-latest.tar.gz: OK
```
Signed-off-by: Integral <integral@member.fsf.org>
466641310f