CORE-38: update snakeyaml

[davidangb]

Updates snakeyaml to latest.

I swear the last time I tried to do this, I ran into conflicts with elasticsearch. But it seems to be working, and passing all unit, integration, and swatomation tests.

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Have you read CONTRIBUTING.md lately? If not, do that first.

I, the developer opening this PR, do solemnly pinky swear that:

• I've followed the instructions if I've made any changes to the API, especially if they're breaking changes
• I've updated the FISMA documentation if I've made any security-related changes, including auth, encryption, or auditing

In all cases:

• Get two thumbsworth of review and PO signoff if necessary
• Verify all tests go green
• Squash and merge. Make sure your branch deletes; GitHub should do this for you.
• Test this change deployed correctly and works on dev environment after deployment