Remove Travis integration as duplicate to our GitHub Actions

[jeffpaul]

Describe your question
It looks like https://github.com/10up/convert-to-blocks/blob/develop/.travis.yml is duplicating what we're doing in https://github.com/10up/convert-to-blocks/blob/develop/.github/workflows/test.yml so I think we can remove the Travis integration and roll with the GitHub Actions for testing. Yay? Nay?

[dinhtungdu]

Agreed! Actually it's my mistake, I didn't remove travis in #6

[jeffpaul]

@dinhtungdu not your fault, Travis was added in after #6.