Prevent API parse error when names contain quotes

[fibbers]

This way, it's possible to call message.setTo(Map.of(name, address)) without first having to escape the name.

This should fix #65.

Note:

• If there are other characters that might also need escaping, I can add those as well. Also, if there's another way of escaping than this simple .replace call, I can change it.
• I didn't add an integration test, but let me know if that's desired.
• I saw in the other tests inside MessageTest that assertEquals are reversed: expected <-> actual. I didn't modify them to keep this PR focused, but just so you know.

[fibbers]

@ibalosh gently pinging you in case you missed some notifications 🙂

What do you think, are there any changes you can think of, or does it look ok?

[ibalosh]

Hi @fibbers Unfortunatelly I no longer work on Postmark project, please check with Active Campaign engineering team.

[dandigangi]

hi @fibbers, the team and I are figuring out what to do here as well as update the maintainer list. We'll follow up!