8d306862ef077f2a71931372dd6a2efa05188c84 ci: Add fuzzbuzz integration (practicalswift)
Pull request description:
Add fuzzbuzz integration.
Just like #15338 enabled optional FreeBSD building via Cirrus CI (`.cirrus.yml`) this PR adds optional fuzzing via fuzzbuzz (`.fuzzbuzz.yml`).
Having this merged makes is easier for people to fuzz Bitcoin Core (via their forked repos) using their fuzzbuzz account and then hopefully submit coverage increasing corpus additions upstreams to to https://github.com/bitcoin-core/qa-assets.
Historically it has been mostly been me and MarcoFalke who submit test cases to `qa-assets`, but with this change hopefully more people will join the hunt for coverage increasing fuzzing inputs :)
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Tree-SHA512: c7d8e354996c673da36cc9add260383c82a5325bfaa7ce6141ad6cd6b7d6adf3a6c900ea2db17fb70147b3625fa7f6a1ff8ba813aeaa299f316d8f6cabb3a65c
