simplicity sys: prepare simplicity-sys 0.8.0 release

[KyrylR]

TL;DR: we are bumping because of braking change of bitcoin_hashes dep

Ran the vendor command with the following command:

nix shell nixpkgs#gnused nixpkgs#coreutils \                      
  --command bash ./vendor-simplicity.sh \
  ./depend /tmp/simplicity-vendor-check.PIsQKe/upstream

On this revision of Simplicity: BlockstreamResearch/simplicity@ba967b1

It is my first time doing such bump, so I am not entirely convinced that it is necessary, but AI reasoning (which is below) looks legit to me

Summary by GPT-6 Astra

Bump simplicity-sys to 0.8.0 ahead of the next Rust Simplicity release

The hash dependency update moved bitcoin_hashes from 0.14 to 1.x. Since simplicity-sys exposes these types in its public API, this is a breaking change and requires a version bump

Update the versioned C symbols, corresponding Rust bindings, and Cargo linking metadata to the 0.8 namespace. Update the workspace dependency requirements and lockfile accordingly. The vendored Simplicity revision and C implementation remain unchange

Verified that rerunning the vendoring script produces no Git diff

[apoelstra]

Can you also add a pub use hashes; to src/lib.rs?

I didn't realize that we were exporting hashes types in our public API, but we are. So we should let users type simplicity_sys::hashes to get "the version of hashes used by simplicity-sys".

[apoelstra]

ACK 731ae17; successfully ran local tests

[KyrylR]

Tagged

[KyrylR]

@apoelstra I am not an owner of the sys package, so I cannot publish it

[apoelstra]

Deleted the tag, which should point to the merge commit (which does not exist yet).

[apoelstra]

Tagged and published.