Update changelog and add credit

Related to #2377
Related to #2405

This was adapted to 3.3-stable from
7b152019da.

CONTRIBUTORS.md

@@ -70,6 +70,7 @@ video tutorials.
  - Mário Freitas
  - GeO4d
  - Marcus Geelnard
+ - Gegy
  - ghuser404
  - Charles Giessen
  - Ryan C. Gordon
@@ -129,6 +130,7 @@ video tutorials.
  - Luflosi
  - lukect
  - Tristam MacDonald
+ - Jean-Luc Mackail
  - Hans Mackowiak
  - Ramiro Magno
  - Дмитри Малышев

README.md

@@ -130,6 +130,9 @@ information on what to include when reporting a bug.
  - [Win32] Bugfix: XInput could reportedly provide invalid DPad bit masks (#2291)
  - [Cocoa] Bugfix: Compilation failed on OS X 10.8 due to unconditional use of 10.9+
    symbols (#2161)
+ - [Cocoa] Bugfix: Full screen windows were resizable by the user (#2377,#2405)
+ - [Cocoa] Bugfix: Full screen windows were miniaturized when clicked on macOS
+   10.15 (#2377,#2405)
  - [Wayland] Added improved fallback window decorations via libdecor (#1639,#1693)
  - [Wayland] Bugfix: Connecting a mouse after `glfwInit` would segfault (#1450)
  - [Wayland] Disabled alpha channel for opaque windows on systems lacking