minor #1032 removing appveyor - windows builds are on GH Actions (weaverryan)

This PR was merged into the main branch.

Discussion
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removing appveyor - windows builds are on GH Actions

Also, travis needs to move to GH actions - `@jrushlow` is going to do that :)

Commits
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93f83e9 removing appveyor - windows builds are on GH Actions

Author: weaverryan