mgba: Update to 0.8.3

0.8.3: (2020-08-03)
Emulation fixes:
- ARM: Fix LDM^ writeback to user-mode register
- ARM: Fix LDM^ {pc} differences (fixes mgba.io/i/1698)
- ARM: Fix edge case with Thumb SBC flags (fixes mgba.io/i/1818)
- GB MBC: Fix MBC1 RAM enable bit selection
- GB MBC: Fix MBC2 bit selection
- GB Memory: Fix OAM DMA from top 8 kB
- GB Video: Always initialize palette
- GBA Savedata: Fix potential corruption when loading a 1Mbit flash save
- GBA Video: Fix invalid read in mode 4 mosaic
- GBA Video: Fix color of disabled screen
- SM83: Fix flags on little endian PowerPC
Other fixes:
- All: Correct format strings for some numbers on Windows (fixes mgba.io/i/1794)
- All: Correct more format strings on Windows (fixes mgba.io/i/1817)
- ARM: Fix decoder detection of branches with ALU and LDR instrctions
- CMake: Fix build with libzip 1.7
- CMake: Add missing dllexports.h file to dev installation
- GB Core: Fix extracting SRAM when none is present
- GBA: Fix leak if attempting to load BIOS multiple times
- GBA Memory: Fix instability on Wii when using AGBPrint
- GBA Savedata: Fix extracting save when not yet configured in-game
- Qt: Fix file handle leak on opening an invalid ROM
- Qt: Fix Italian RTC translation (fixes mgba.io/i/1798)
- Qt: Add missing option for Wisdom Tree in overrides list
- Qt: Fix stability regression on AMD drivers (fixes mgba.io/i/1791)
- Util: Fix crash if PNG header fails to write
Misc:
- FFmpeg: Use range coder for FFV1 to reduce output size
- Qt: Add per-page scrolling to memory view (fixes mgba.io/i/1795)
- Qt: Add setting to display ROM filename in title (closes mgba.io/i/1784)

(nia)