Log Message:
svt-av1: update to 2.1.0.

2.2.0 is out, but 2.1.1 removed the decoder. Not sure what to do about that.

## [2.1.0] - 2024-05-17

API updates
- One config parameter added within the padding size. Config param structure \ 
size remains unchanged
- Presets 6 and 12 are now pointing to presets 7 and 13 respectively due to the \ 
lack of spacing between the presets
- Further preset shuffling is being discussed in #2152

Encoder
- Added variance boost support to improve visual quality for the tune vq mode
- Improve the tradeoffs for the random access mode across presets:
-   Speedup of 12-40% presets M0, M3, M5 and M6 while maintaining similar \ 
quality levels
-   Improved the compression efficiency of presets M11-M13 by 1-2% (!2213)
- Added ARM optimizations for functions with c_only equivalent

Cleanup Build and bug fixes and documentation
- Use nasm as a default assembler and yasm as a fallback
- Fix performance regression for systems with multiple processor groups
- Enable building SvtAv1ApiTests and SvtAv1E2ETests for arm
- Added variance boost documentation
- Added a mailmap file to map duplicate git generated emails to the appropriate \ 
author

## [2.0.0] - 2024-03-13

Major API updates
- Changed the API signaling the End Of Stream (EOS) with the last frame vs with \ 
an empty frame
- OPT_LD_LATENCY2 making the change above is kept in the code to help devs with \ 
integration
- Removed the 3-pass VBR mode which changed the calling mechanism of multi-pass VBR
- Moved to a new versioning scheme where the project major version will be \ 
updated everytime API/ABI is changed

Encoder
- Improve the tradeoffs for the random access mode across presets:
-   Speedup presets MR by ~100% and improved quality along with tradeoff \ 
improvements across the higher quality presets (!2179)
-   Improved the compression efficiency of presets M9-M13 by 1-4% (!2179)
-   Simplified VBR multi-pass to use 2 passes to allow integration with ffmpeg
- Continued adding ARM optimizations for functions with c_only equivalent
- Replaced the 3-pass VBR with a 2-pass VBR to ease the multi-pass integration \ 
with ffmpeg
- Memory savings of 20-35% for LP 8 mode in preset M6 and below and 1-5% in \ 
other modes / presets

Cleanup and bug fixes and documentation
- Various cleanups and functional bug fixes
- Update the documentation to reflect the rate control changes