Bump submodule to 3.0.0-rc.2

[thunderbiscuit]

No description provided.

[reez]

I can’t remember the exact release flow here, so that’s why I’m asking: do we need to update the bdk-ffi lockfile before merging this so the lockfile version matches the bumped submodule/Cargo.toml version? Right now the submodule’s Cargo.toml says 3.0.0-rc.2, but Cargo.lock still has bdk-ffi at 3.0.0-alpha.0.

[thunderbiscuit]

Wow really good catch. I'm opening a PR on bdk-ffi to fix the lockfile (bitcoindevkit/bdk-ffi#1005), but we should also try to see where we need to update our docs on release workflows so that step is included.

I also found something we could add to our build scripts which check whether the lockfile is in line with what cargo expects. You add --locked to your cargo build command, and if the lockfile is not quite right cargo will just stop the build and warn you. I think adding this doesn't cost much and would flag those little lockfile update issues when they arise.

[thunderbiscuit]

You can see the failure here: https://github.com/bitcoindevkit/bdk-python/actions/runs/26170320748/job/76985853492, which should resolve once we merge #1005 on bdk-ffi and update the submodule here!

[reez]

ACK 3b2cd8f