Update graphics/glfw to 3.2.1

Changes:
3.2.1
=====
Vulkan improvements
-------------------
Add support for statically linking the Vulkan loader

Misc improvements and bug fixes
-------------------------------
Fixes for a number of bugs that together affect all supported platforms.

3.2
===
Support for Vulkan
------------------
GLFW now supports basic integration with Vulkan with glfwVulkanSupported,
glfwGetRequiredInstanceExtensions, glfwGetInstanceProcAddress,
glfwGetPhysicalDevicePresentationSupport and glfwCreateWindowSurface.
Vulkan header inclusion can be selected with
GLFW_INCLUDE_VULKAN.

Window mode switching
---------------------
GLFW now supports switching between windowed and full screen modes and updating
the monitor and desired resolution and refresh rate of full screen windows with
glfwSetWindowMonitor.

Window maxmimization support
----------------------------
GLFW now supports window maximization with glfwMaximizeWindow and the
GLFW_MAXIMIZED hint and attribute.

Window input focus control
--------------------------
GLFW now supports giving windows input focus with glfwFocusWindow.

Window size limit support
-------------------------
GLFW now supports setting both absolute and relative window size limits with
glfwSetWindowSizeLimits and glfwSetWindowAspectRatio.

Localized key names
-------------------
GLFW now supports querying the localized name of printable keys with
glfwGetKeyName, either by key token or by scancode.

Wait for events with timeout
----------------------------
GLFW now supports waiting for events for a set amount of time with
glfwWaitEventsTimeout.

Window icon support
-------------------
GLFW now supports setting the icon of windows with glfwSetWindowIcon.

Raw timer access
----------------
GLFW now supports raw timer values with glfwGetTimerValue and
glfwGetTimerFrequency.

Joystick connection callback
----------------------------
GLFW now supports notifying when a joystick has been connected or disconnected
with glfwSetJoystickCallback.

Context-less windows
--------------------
GLFW now supports creating windows without a OpenGL or OpenGL ES context with
GLFW_NO_API.

Run-time context creation API selection
---------------------------------------
GLFW now supports selecting the context creation API at run-time with the
GLFW_CONTEXT_CREATION_API window hint value.

Error-free context creation
---------------------------
GLFW now supports creating OpenGL and OpenGL ES contexts that do not emit errors
with the GLFW_CONTEXT_NO_ERROR window hint, provided
the machine supports the `GL_KHR_no_error` extension.

CMake config-file package support
---------------------------------
GLFW now supports being used as a
config-file package from other projects for
easy linking with the library and its dependencies.

(leot)