Feat/cosine_annealing_lr

[L-M-Sherlock]

fixes #21

[dae]

Sorry, this took a conflict. No problems with the Rust code jump out at me. 👍

[asukaminato0721]

the test seems interesting

---- cosine_annealing::test_lr_scheduler stdout ----
thread 'cosine_annealing::test_lr_scheduler' panicked at 'assertion failed: `(left == right)`
  left: `[0.1, 0.09045084971874769, 0.06545084971874847, 0.03454915028125373, 0.009549150281252953, 0.0, 0.00954915028125269, 0.034549150281252376, 0.0654508497187476, 0.09045084971874953, 0.10000000000000367]`,
 right: `[0.1, 0.09045084971874785, 0.06545084971874875, 0.034549150281253875, 0.009549150281252989, 0.0, 0.009549150281252692, 0.03454915028125239, 0.06545084971874746, 0.09045084971874952, 0.10000000000000353]`', src/cosine_annealing.rs:76:5

maybe need to adjust the precision.