fixes Github Actions failures

[dpfens]

Github Actions failing due to new release of pyyaml==5.4 this change will ensure that version 5.3 is used. There may be a better/simpler way to account for this issue, just let me know.

[stefanv]

👋 @dpfens, thanks for the fix! I don't think we can pin to such a specific range of pyyaml, so could we rather address the error introduced?

[dpfens]

@stefanv Makes sense. Changing this line to use the yaml.Loader instead of yaml.FullLoader no longer raises the error. yaml.BaseLoader should also work, but it could introduce new issues.

[stefanv]

This seems to be an ongoing issue for PyYAML; the issue @dpfens mentioned above is also the one that tracks this problem. They sorted it out in 5.2 apparently, and now it is appearing again.

@dpfens Thanks for addressing, this seems like a fine workaround (strictly speaking unnecessary, but that's for PyYAML to address).

[jarrodmillman]

LGTM. We are removing networkx/readwrite/nx_yaml.py, so in a a couple months we won't have to worry about this anymore.