<!--- Provide a general summary of your changes in the title above -->
## Types of changes
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- [ ] Bug fix (a non-breaking change which fixes an issue)
- [ ] New feature (a non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to change)
## Description
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<!--- Why is this change required? What problem does it solve? -->
<!--- If it resolves an open issue, please link to the issue here. For example "Resolves: #1337" -->
## Checklist:
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<!--- If your change requires a documentation PR, please link it appropriately -->
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- [ ] My change requires a change to the documentation.
- [ ] I have updated the documentation accordingly. (PR: #)
- [ ] I have added tests to cover my changes (if not applicable, please state why)
- [ ] All new and existing tests are passing.
* fix: appveyor test failure
* ci: bring back yarn cache
* ci: turn off matrix
* refactor: use babel instead of esm in jest
* refactor: use es modules in fixtures
