fetch-configlet: DRY/sync with version in configlet repo

[ee7]

Or reach feature parity with it.

For the fetch-configlet script in this repo, which is designed to be used only in the GitHub Actions environment, we could also consider a gh-only implementation like:

name='configlet.tar.gz'
gh -R exercism/configlet release download --output "${name}" \
  --pattern 'configlet_*_linux_x86-64.tar.gz'
tar xzf "${name}" -C bin/
rm "${name}"

[SaschaMann]

The gh implementation would avoid the token issues, seems like a good idea to change to that.

[ee7]

Yeah. We have to pass in a token either way, but gh always makes authenticated requests. So that's more robust, at least in the sense that it fails noisily if the token handling is bad.

I've created #107, which uses the script from the top post in this issue.