fix(Keyboard): remove warnings raised by arduino-lint

WARNING: library.properties maintainer value Arduino <info@arduino.cc> starts with "Arduino". 3rd party libraries are
         not maintained by Arduino. (Rule LP027)
WARNING: library.properties maintainer value Arduino <info@arduino.cc> contains "Arduino". 3rd party libraries are not
         maintained by Arduino. (Rule LP057)

Signed-off-by: Frederic Pillon <frederic.pillon@st.com>

Author: fpistm

libraries/Keyboard/library.properties

@@ -1,9 +1,9 @@
 name=Keyboard
 version=1.1.0
-author=Arduino
-maintainer=Arduino <info@arduino.cc>
-sentence=Allows an Arduino/Genuino board with USB capabilities to act as a Keyboard.
-paragraph=This library plugs on the HID library. It can be used with or without other HID-based libraries (Mouse, Gamepad etc)
+author=Arduino, stm32duino
+maintainer=stm32duino
+sentence=Allows a STM32 based board with USB capabilities to act as a Keyboard.
+paragraph=This library plugs on the HID implementation provided by the core.
 category=Device Control
 url=http://www.arduino.cc/en/Reference/Keyboard
 architectures=stm32