Update CI

[aminya]

See the running actions here: https://github.com/aminya/QML.jl/actions/runs/81314887

Hopefully, makes it easier to see the problems of the building/tests once the JIL stuff are ready.

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Appveyor app should be removed from the repository to prevent it from throwing error.

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To make the automatic deployment work:

# ]add DocumenterTools
using QML, DocumenterTools
DocumenterTools.genkeys(QML)

DOCUMENTER_KEY:
Add the public key to https://github.com/barche/QML.jl/settings/keys
Add the private key to https://github.com/barche/QML.jl/settings/secrets

[barche]

Aha, cool, I didn't know about this. I propose hloding off merging this until we have a "draft" jlqml package that we can use, similarly to the tests for CxxWrap:

https://github.com/JuliaInterop/CxxWrap.jl/blob/892da39121257c2b45b130bcd639d25470c4720c/.travis.yml#L11

[barche]

Thanks, finally merged this, though it was in need of some changes because @bramtayl used the same approach in PR #77