release: ark-groth16 v0.4.0 (arkworks-rs#47)

* (semi-) Automate the release process (arkworks-rs#46)

* chore: Release {{crate_name}} version {{version}}

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Co-authored-by: mmagician <marcin.gorny.94@protonmail.com>
Co-authored-by: github-actions <github-actions@github.com>

Release v0.3.0 (arkworks-rs#32)

* release v0.3.0

* fmt

(cargo-release) ark-groth16 version 0.2.0