v3.20.2: OpenTracks

Changes:
- Elevation gain and loss are integers instead of floats
- Ask for permission before using Bluetooth by a Toast message

Bugfix:
- Set FLAG_IMMUTABLE for PendingIntents to avoid crash on Android 12
- Cadence sensor returns 0 instead of None when user is not pedaling
- Speed sensor returns 0 instead of the last speed when it's stopped
- With sensors, moving time stops when is not moving