cerbero: Add a dotted progress bar for urllib downloads
Also add a 20s timeout (same as wget) so that we timeout on download instead of timing out the entire job on CI. The global socket timeout with CPython is apparently -1, aka never timeout.
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Also add a 20s timeout (same as wget) so that we timeout on download instead of timing out the entire job on CI. The global socket timeout with CPython is apparently -1, aka never timeout.