Update Changelog + Readme for v4.0.0 #205

Job	Run time
NIF 2.16 - aarch64-unknown-linux-gnu (ubuntu-22.04)	46s
NIF 2.16 - aarch64-unknown-linux-musl (ubuntu-22.04)	54s
NIF 2.16 - aarch64-apple-darwin (macos-12)	1m 4s
NIF 2.16 - riscv64gc-unknown-linux-gnu (ubuntu-22.04)	44s
NIF 2.16 - x86_64-apple-darwin (macos-12)	45s
NIF 2.16 - x86_64-unknown-linux-gnu (ubuntu-22.04)	37s
NIF 2.16 - x86_64-unknown-linux-musl (ubuntu-22.04)	1m 2s
NIF 2.16 - x86_64-pc-windows-gnu (windows-2019)	1m 38s
NIF 2.16 - x86_64-pc-windows-msvc (windows-2019)	1m 18s
NIF 2.15 - aarch64-unknown-linux-gnu (ubuntu-22.04)	43s
NIF 2.15 - aarch64-unknown-linux-musl (ubuntu-22.04)	1m 12s
NIF 2.15 - aarch64-apple-darwin (macos-12)	48s
NIF 2.15 - riscv64gc-unknown-linux-gnu (ubuntu-22.04)	38s
NIF 2.15 - x86_64-apple-darwin (macos-12)	1m 1s
NIF 2.15 - x86_64-unknown-linux-gnu (ubuntu-22.04)	27s
NIF 2.15 - x86_64-unknown-linux-musl (ubuntu-22.04)	1m 6s
NIF 2.15 - x86_64-pc-windows-gnu (windows-2019)	2m 20s
NIF 2.15 - x86_64-pc-windows-msvc (windows-2019)	1m 18s
	18m 21s

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