Fetch red background fix from libtcod.

HexDecimal · HexDecimal · commit 80afe770400e · 2022-05-02T11:43:37.000-07:00
Fixes #116
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -4,6 +4,8 @@ Changes relevant to the users of python-tcod are documented here.
 This project adheres to [Semantic Versioning](https://semver.org/) since version `2.0.0`.
 
 ## [Unreleased]
+### Fixed
+- SDL renderers were ignoring tiles where only the background red channel was changed.
 
 ## [13.6.1] - 2022-03-29
 ### Changed
diff --git a/libtcod b/libtcod
@@ -1 +1 @@
-Subproject commit 577f83b39ca25dcc50051751182ba1defe9b62c4
+Subproject commit 6f0a9bc8c31f769709299f248681b57a6f9659be
