GitLab

This PR includes a pico-sdk built using the fix in
https://github.com/raspberrypi/pico-sdk/pull/864

To properly fix it requires a new pico-sdk release. but until then I am
building against my own fork of pico-sdk and including the binary.
When 1.3.2 is out (and assuming my PR is approved) I'll update the pico-sdk
link.

Fixes #614