Keymap: Keymap update (#4579)

* Add YREG keycode

* Add GM layer

* Set tapping term to 105

* update tapping term

users/zer09/zer09.h

@@ -3,16 +3,24 @@
 
 #include "quantum.h"
 
-enum custom_keycodes { CK_SAFE = SAFE_RANGE, RGUP, RGDWN, NEWPLACEHOLDER };
+enum custom_keycodes {
+  CK_SAFE = SAFE_RANGE,
+  RGUP,
+  RGDWN,
+  YREG,
+  NEW_SAFE_RANGE
+};
 
 #define _______ KC_TRNS
 #define KC_RGUP RGUP
 #define KC_RGDWN RGDWN
+#define KC_YREG YREG
 
 #define _BL 0 // The base layer
 #define _UL 1 // The up layer
 #define _DL 2 // The down layer
 #define _VL 3 // The shifted up layer
 #define _AL 4 // The assorted layer
+#define _GM 5
 
 #endif