Hash mismatches when fetching indexes in CI

[clay-lake]

Recently CI has been failing sporadically when fetching indexes during an initial apt update or subsequent chisel cuts. As seen in the second log given below, this may be because some requested resources return with an HTTP 404. However the resources cannot actually be missing since the same step may pass on subsequent runs.

Examples:

• https://github.com/canonical/chisel-releases/actions/runs/15285063732/job/42993176354#step:10:55
• https://github.com/canonical/chisel-releases/actions/runs/15256940967/job/42906731498#step:10:289

[lczyk]

i've come across this too very recently :<