New boards; minor fixes

[Note that this release is incorrectly tagged as 3.12.0 instead of v3.12.0.]

New boards:

• Neo Trinkey. #156. Thanks @ladyada.
• Seeed Wio Terminal. #154. Thanks @mcauser.
• Rabid Prototypes Tau. #123, Thanks @ealasu.
• StackRduino-M0-PRO. #153. Thanks @StackRduino.
• CP Sapling m0. #150. Thanks @skerr92.
• Itaca Innovation uChip. #147. Thanks @ITACAInnovation.

Fixes:

• Fix capitalization of JLinkExe command in Makefile. #155. Thanks @xorbit.
• Update pins on Adafruit Feather CAN. #152. Thanks @ladyada.
• Fix README typo. #149. Thanks @e28eta.