Prep for v1.30.0

[odow]

Basic

• [x] version field of Project.toml has been updated
  • If a breaking change, increment the MAJOR field and reset others to 0
  • If adding new features, increment the MINOR field and reset PATCH to 0
  • If adding bug fixes or documentation changes, increment the PATCH field

Documentation

• [x] Add a new entry to docs/src/changelog.md, following existing style

Tests

• [x] https://github.com/jump-dev/MathOptInterface.jl/actions/runs/9201576837

[odow]

@blegat PolyJuMP and SumOfSquares are both failing. Is that expected?

[blegat]

Yes, they need the master versions of some of their dependencies