Allow treetime v0.11 (no breaking changes)

[corneliusroemer]

Support treetime v0.11. No changes necessary as no breaking changes in treetime.

See changes here: neherlab/treetime@v0.10.1...v0.11.1

Checklist

• Checks pass: Being tested on treetime v0.11 in CI, so that's good! https://github.com/nextstrain/augur/actions/runs/6112050391/job/16588676615#step:5:401
• Successfully used in production myself for quite a few weeks already (and Richard too)
• If making user-facing changes, add a message in CHANGES.md summarizing the changes in this PR

Post release

• Need to update bioconda recipe dependencies once this is released

[corneliusroemer]

We're in a bind here due to treetime still being v0, which means we can't distinguish between breaking changes and feature releases. It's a bit annoying to have to bump and review each time we want to use a new treetime feature bump.