adapt mining.capnp with interruptWait

[plebhash]

Bitcoin Core branches master and 30.x now have a new BlockTemplate.interruptWait

that's going to be needed for stratum-mining/sv2-apps#81, which aims to remove some workarounds for some bugs that were found on v30 and patched on v30.1+

my WIP is currently pointing to our fork https://github.com/stratum-mining/bitcoin-capnp-types, so this PR aims to allow us to eventually switch back to using this repo as source-of-truth

also, I believe some kind of versioning system should be considered here, as proposed on #4

[Sjors]

v30.2 should be out in a few days. v30.0 and v30.1 were retracted to due to a wallet bug. That's not relevant for sv2 at all, but it's probably best to bump the minimum version to v30.2 once it's out.

bitcoin/bitcoin@v30.1...v30.2: includes bitcoin/bitcoin#33511

[rustaceanrob]

Looks good to me. As far as versioning I think this master should follow BItcoin Core master as much as possible, and we tag releases as Bitcoin Core releases them. Would you or someone else from SV2 like to have crate publishing rights?