Automatic update of fbcode/foxi to 81e1683d6348eee4b5ed1145222dc2c41be4269c (#18596)

Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/18596

Previous import was 2bcc4064c90e87b9638615c733485f07c47b7558

Included changes:
- **[81e1683](https://github.com/houseroad/foxi/commit/81e1683)**: Merge pull request #9 from zrphercule/add_foxi_quantization <Rui Zhu>
- **[580559c](https://github.com/houseroad/foxi/commit/580559c)**: char=>uint8 <zrphercule>
- **[1a572f7](https://github.com/houseroad/foxi/commit/1a572f7)**: add quantization <zrphercule>

Reviewed By: zrphercule

Differential Revision: D14677404

fbshipit-source-id: 09429b3bf0e7783a25b8145020e505761bad887d

diff --git a/third_party/foxi b/third_party/foxi
index 2bcc406..81e1683 160000 (submodule)
--- a/third_party/foxi
+++ b/third_party/foxi
@@ -1 +1 @@
-Subproject commit 2bcc4064c90e87b9638615c733485f07c47b7558
+Subproject commit 81e1683d6348eee4b5ed1145222dc2c41be4269c