Autoupdate broke in 3.5.0

[sarathms]

A recently applied fix for #1318 has introduced a bug in the autoupdate process which now prevents the app from automatically updating from 3.5.0 or 3.5.1.

From the logs:

[2021-06-24 00:08:13.360] [info]  Found version 3.5.1 (url: OONI-Probe-3.5.1-mac.zip,
OONI-Probe-3.5.1.dmg)
[2021-06-24 00:08:13.669] [info]  A new update is available. Downloading now...
[2021-06-24 00:08:13.676] [info]  Update not available

Risk Mitigation:

We have unpublished the affected versions 3.5.0 and 3.5.1 from Github releases to minimize the number of users automatically upgrading to those versions. Users who are still running 3.4.0 should be able to update directly to the next version that will have a fix for this bug.

Other steps to address this kind of an issue in future:

• Automate testing the auto-update feature in CI
• Have a mechanism to show notices in the app on startup to be able to help out users stuck in unupgradable versions.