planck/premek layout - thumb shift, mouse middleclick (#3111)

* Update readme.md

updated links, hope those are the correct ones

* planck premek - left thumb shift

* middleclick key

* mod tap thumb-shift, space

* update layout description

keyboards/planck/keymaps/premek/config.h

@@ -3,6 +3,7 @@
 
 #include "../../config.h"
 
+
 /*
  * MIDI options
  */
@@ -26,4 +27,4 @@
 /* override number of MIDI tone keycodes (each octave adds 12 keycodes and allocates 12 bytes) */
 //#define MIDI_TONE_KEYCODE_OCTAVES 2
 
-#endif
+#endif