Upgrade macOS version in GitHub actions

[menon-karthik]

Problem

The current Github Actions run macOS-11 and macOS-12. These are either not available anymore or will shortly be not available. See here.

Solution

I will update the macOS versions in our GitHub actions. We already included macos-latest and ubuntu-latest in #113. That required using conda-incubator to find conda and add it to the path.

Additional context

Just creating this issue to record the upcoming change and also the change already made in #113.

Code of Conduct

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