Update changelog and add credit

Related to #1951

(cherry picked from commit 1461c59aa2426b25503102e62bc8f4b65e079c5f)
diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
index c17b737..e80a0fe 100644
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -183,6 +183,7 @@
  - Joao da Silva
  - Daniel Sieger
  - Daniel Skorupski
+ - Slemmie
  - Bradley Smith
  - Cliff Smolinsky
  - Patrick Snape
diff --git a/README.md b/README.md
index 2bd4b63..cc2667e 100644
--- a/README.md
+++ b/README.md
@@ -137,6 +137,7 @@
  - [X11] Bugfix: `glfwPostEmptyEvent` could be ignored due to race condition
    (#379,#1281,#1285,#2033)
  - [X11] Bugfix: Dynamic loading on NetBSD failed due to soname differences
+ - [X11] Bugfix: Left shift of int constant relied on undefined behavior (#1951)
  - [Wayland] Added support for key names via xkbcommon
  - [Wayland] Bugfix: Key repeat could lead to a race condition (#1710)
  - [Wayland] Bugfix: Activating a window would emit two input focus events