Update Eigen to commit:21e89b930c6af56dbdaeea2a91d8b9d6fd2c208a CHANGELOG ========= 21e89b930 - Enable default behavior for pmin<PropagateFast>, predux_min, etc 4fdf87bbf - clean up intel packet reductions a7f183cad - Add factory/getters for quat coeffs in both orders d81aa18f4 - Explicitly construct the scalar for non-implicitly convertible types PiperOrigin-RevId: 766811637 Change-Id: I6184e3c71bb418f61715e8c3d5fb29d357749417