Update pystog to v0.4.7

[peterfpeterson]

Previously it was pinned to v0.2.7 and this moves it to v0.4.7.

There is no associated issue.

To test:

The new version should still pass all the tests.

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[sf1919]

Looks like the release note in Powder Diffraction is not in a sub-folder so it's not being picked up.

[KedoKudo]

Looks good 👍