docs: add release notes for 10.6.8
docs: add release notes for 10.6.8

Signed-off-by: Emil Velikov <4c996f2f093ddd0585a556460b4cc3ba555546ef@gmail.com>
(cherry picked from commit 91c6302734574e91424a7ccb52b6368b712366cc)

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler