boards: stm32f072b_disco: Update outdated link

This commit updates the oudated link to the "SK Pang CAN breakout
board" (with MCP2561FD transceiver) product page.

Signed-off-by: Stephanos Ioannidis <[email protected]>

Author: stephanosio

boards/arm/stm32f072b_disco/doc/index.rst

@@ -216,4 +216,4 @@ References
    http://www.st.com/resource/en/reference_manual/dm00031936.pdf
 
 .. _SK Pang CAN breakout board:
-   http://skpang.co.uk/catalog/canbus-can-fd-breakout-board-5v-p-242.html
+   https://www.skpang.co.uk/products/can-bus-can-fd-breakout-board-5v-supply-and-5v-logic