6.0.0 version still pulls glfw-3.3.9

Ways to reproduce:
* Create a new project, add `glfw-sys = { version = "6", features = ["src-build"] }` dependency
* Inspect the registry:
```
less ~/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/glfw-sys-6.0.0/glfw/include/GLFW/glfw3.h | grep VERSION
#define GLFW_VERSION_MAJOR          3
#define GLFW_VERSION_MINOR          3
#define GLFW_VERSION_REVISION       9
```