deps: update fiat-crypto requirement from 0.1.11 to 0.2.1 #457

Job	Run time
Build and check benchmarks	2m 2s
Build documentation	23s
Linux/ARM - Release tests (i686-unknown-linux-gnu)	30s
Linux/ARM - Release tests (armv7-unknown-linux-gnueabihf)	28s
Linux/ARM - Release tests (mips64-unknown-linux-gnuabi64)	23s
no_std build (stable)	1m 59s
no_std build (nightly)	2m 4s
Tests w. sanitizers	1m 44s
test (stable, ubuntu-latest)	1m 44s
test (stable, macos-latest)	1m 40s
test (stable, windows-latest)	1m 10s
test (beta, ubuntu-latest)	1m 43s
test (beta, macos-latest)	1m 42s
test (beta, windows-latest)	1m 43s
test (nightly, ubuntu-latest)	1m 40s
test (nightly, macos-latest)	1m 41s
test (nightly, windows-latest)	1m 41s
test (1.64.0, ubuntu-latest)	1m 43s
test (1.64.0, macos-latest)	1m 41s
test (1.64.0, windows-latest)	1m 42s
WebAssembly - Release build (wasm32-unknown-unknown)	26s
	29m 49s

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