Update SodaqCore-samd to version 1.8.6

[matthias-mueller]

It currently sits at 1.6.20 which is severely outdated.

The current stable SodaqCore-samd version is 1.8.6:

https://forum.sodaq.com/t/sodaqcore-samd-v1-8-6/3342

Although there has been some discussion/work in #93 it seems that no upgrade actually happened.

[maxgerhardt]

+1 to this -- the branching / tag structure on the https://github.com/SodaqMoja/SodaqCore-samd/ core is also pretty damn confusing in the SODAQ core. The default branch points to 1.6.15. There are no releases on the github, only tags.

[matthias-mueller]

Thanks for handling this @valeros !

[valeros]

@matthias-mueller Please retest with the upstream version:

[env:sodaq_explorer]
platform = https://github.com/platformio/platform-atmelsam.git
framework = arduino
board = sodaq_explorer

[matthias-mueller]

@valeros Compilation works and the first tests look okay:

[env:sodaq_sff]
platform = https://github.com/platformio/platform-atmelsam.git
board = sodaq_sff
framework = arduino

[keestux]

Thanks for the update