v0.3.0 release

[brynpickering]

Checklist

Any checks which are not relevant to the PR can be pre-checked by the PR creator.
All others should be checked by the reviewer(s).
You can add extra checklist items here if required by the PR.

• CHANGELOG updated
• Tests added to cover contribution
• Documentation updated

Pre-release

• Re-run tutorial Jupyter notebooks (pytest examples/ --overwrite).
• Make sure documentation builds without errors (mike deploy [version], where [version] is the current patch release of the form X.Y.Z).
• Make sure the [changelog][changelog] is up-to-date, especially that new features and backward incompatible changes are clearly marked.

Create release

• Bump the version number in pam/__init__.py
• Update the [changelog][changelog] with final version number of the form vX.Y.Z, release date, and github compare link (at the bottom of the page).
• Commit with message Release vX.Y.Z, then add a vX.Y.Z tag.
• Create a release pull request to verify that the conda package builds successfully.
• Once the PR is approved and merged, create a release through the GitHub web interface, using the same tag, titling it Release vX.Y.Z and include all the changelog elements that are not flagged as internal.

[brynpickering]

Waiting on #258

[brynpickering]

@Theodore-Chatziioannou ready for review