Update nightly version, update embassy

[hdoordt]

For now, this yields some linker issues. The produced binary is too large to fit into the FLASH region. Temporarily increasing its size to 100K in order to be able to run cargo size, the linker gives:

[...]
rust-lld: error: undefined symbol: _critical_section_1_0_acquire
[...]
rust-lld: error: undefined symbol: _critical_section_1_0_release
[..]

[diondokter]

That linker issue can be solved when you give the cortex-m dependency the new feature critical-section-single-core

[hdoordt]

Thanks!