v0.6a pre-release

Pre-release build for the next revision 0.6a

• Updated SDCard library to latest revision

Installation

Hold down the 'BOOTSEL' button while plugging the Raspberry Pi Pico into a PC using a MicroUSB cable.
Wait a moment for the Pico to appear as an external drive.
Drag the release ".UF2" file on to the mounted Raspberry Pi Pico.
Wait for the Raspberry Pi Pico to unmount and reboot.