Disable security with downloading sccache tarball

Some organizations use a firewall that intercepts SSL communications and
replaces the authentication token with an organization-wide token that
is just supposed to be accepted. Browsers can be locally configured for
this intentional trickery, but it's a little more tricky for the use of
`curl` in a batch script that is shared with external collaborators.

The easiest solution is to just disable the security for the `curl`
download. This makes the script more susceptible to "man in the middle"
attacks, but it's probably easier to just slip malware in the public
repos anyway.
3 jobs for disable-curl-auth