Update module github.com/go-gl/mathgl to v1.2.0

Author: renovate[bot]

go.mod

@@ -8,7 +8,7 @@ require (
 	github.com/galaco/source-tools-common v0.1.0
 	github.com/galaco/vmf v1.0.0
 	github.com/go-gl/gl ae072cafe09d
-	github.com/go-gl/mathgl v1.0.0
+	github.com/go-gl/mathgl v1.2.0
 	github.com/golang-source-engine/filesystem v0.1.4
 	github.com/gotk3/gotk3 v0.0.0-20191010201156-711c17fcaec0 // indirect
 	github.com/inkyblackness/imgui-go/v4 v4.5.0