driver::hid::base: Add isKeyPressed() to the NoKeyboard classes

Other parts of Kaleidoscope require the NKRO and Boot keyboard classes  to have
an `isKeyPressed()` method, which our base classes did not provide - until now.

Signed-off-by: Gergely Nagy <algernon@keyboard.io>

src/kaleidoscope/driver/hid/base/Keyboard.h

@@ -54,6 +54,9 @@ class NoBootKeyboard {
   bool wasAnyModifierActive() {
     return false;
   }
+  bool isKeyPressed(uint8_t code) {
+    return false;
+  }
 
   uint8_t getLeds() {
     return 0;
@@ -83,6 +86,9 @@ class NoNKROKeyboard {
   bool wasAnyModifierActive() {
     return false;
   }
+  bool isKeyPressed(uint8_t code) {
+    return false;
+  }
 
   uint8_t getLeds() {
     return 0;