Encode all `.png` iOS screenshots as `.jpg`

Prepare 0.5.1 project release (#1275)

Prepare 0.5.0 project release (#1240)

Prepare 0.4.3 project release (#1231)

Prepare 0.4.2 project release (#1213)

Prepare 0.4.1 project release (#1204)

Prepare 0.4.0 project release (#1202)

Prepare 0.3.3 project release (#1178)

Additionally:
- set `ConditionalBackdropFilter.enabled` to `false` for all platforms

Remove alpha layer from PNG screenshots of iPad and iPhone (#1169)

Prepare 0.3.1 project release (#1165)