python requirements.txt: pyocd and pyyaml conflict

[attdona]

scripts/requirements.txt declare pyocd==0.16.1 that require pyyaml>=4.2b1,<5.0.

To avoid pip install -r script/requirements.txt failure I've changed:

PyYAML>=3.12

into:

PyYAML==4.2b4

Is it ok or did I miss something?

[mbolivar]

Adding @MaureenHelm as an FYI.

@attdona, I think this is a pyOCD bug, not a Zephyr bug, for reasons explained here:

https://github.com/mbedmicro/pyOCD/issues/582

I'm closing this as a result. Please reopen if you disagree.