contrib: bump minimum required glslang version

Bumping this allows us to drop some backwards-compatibility patches in
the libplacebo contribs, by ensuring that a proper versioned glslang is
always available.

Version 10 of glslang is the first release including the new style build
info header, and is therefore also the minimum dependency required by
newer glslang versions. It makes a natural candidate to start requiring.

contrib/src/glslang/rules.mak

@@ -4,7 +4,7 @@ GLSLANG_VERSION := 11.10.0
 GLSLANG_URL := https://github.com/KhronosGroup/glslang/archive/refs/tags/$(GLSLANG_VERSION).tar.gz
 
 PKGS += glslang
-ifeq ($(call need_pkg,"glslang"),)
+ifeq ($(call need_pkg,"glslang >= 10"),)
 PKGS_FOUND += glslang
 endif