Update git submodules
- Update skins/MinervaNeue from branch 'REL1_39' to 684202c592a5b4a245c788a6f6082066aa174cc4
- Localisation updates from https://translatewiki.net.
Change-Id: I4ba66c821c0b9ff36231d4ce3078a88c502bc33a
- Localisation updates from https://translatewiki.net.