Upgrade pygame version to 2.6.0 (#3025)

This allows one to install pygame binaries for Python-3.11/3.12 runtime, while PyGame-2.1.2 was only available up to python-3.10, see https://pypi.org/project/pygame/2.1.2/#files

Fixes #3023

.ci/docker/requirements.txt

@@ -64,7 +64,7 @@ pyopengl
 gymnasium[mujoco]==0.27.0
 timm
 iopath
-pygame==2.1.2
+pygame==2.6.0
 pycocotools
 semilearn==0.3.2
 torchao==0.0.3