v2.1.0 breaks no_std support

[CryZe]

https://github.com/LiveSplit/livesplit-core/runs/1835592754#step:6:188

error[E0433]: failed to resolve: use of undeclared crate or module `std`
   --> /home/runner/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/ordered-float-2.1.0/src/lib.rs:349:26
    |
349 |     fn classify(self) -> std::num::FpCategory { self.0.classify() }
    |                          ^^^ use of undeclared crate or module `std`

error[E0407]: method `mul_add` is not a member of trait `Float`
   --> /home/runner/.cargo/registry/src/git.luolix.top-1ecc6299db9ec823/ordered-float-2.1.0/src/lib.rs:359:5
    |
359 |     fn mul_add(self, a: Self, b: Self) -> Self { OrderedFloat(self.0.mul_add(a.0, b.0)) }
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not a member of trait `Float`

....

[mbrubeck]

Oops. Very sorry about this. This is now fixed in version 2.1.1 by 6f96e4c. CC #73.

I'll make sure to get continuous integration in place before the next release, so I can't forget to test every configuration.