Import vec to bridges/primitives/header-chain (#6031)
# Description I'm unable to build a bridge library due to the errors below, so I am adding the explicit import to `sp_std::vec`. ## Integration Projects using it can update their dependency. We are using the branch `stable2407` (mixed them up in my branch). ## Errors ``` error: cannot find macro `vec` in this scope --> /Users/drew/.cargo/git/checkouts/polkadot-sdk-cff69157b985ed76/88c32501/bridges/primitives/header-chain/src/justification/verification/mod.rs:99:19 | 99 | let mut route = vec![]; | ^^^ | help: consider importing one of these items | 23 + use scale_info::prelude::vec; | 23 + use sp_std::vec; | error: cannot find macro `vec` in this scope --> /Users/drew/.cargo/git/checkouts/polkadot-sdk-cff69157b985ed76/88c32501/bridges/primitives/header-chain/src/justification/verification/optimizer.rs:135:36 | 135 | duplicate_votes_ancestries_idxs: vec![], | ^^^ | help: consider importing one of these items | 19 + use scale_info::prelude::vec; | 19 + use sp_std::vec; | error: cannot find macro `vec` in this scope --> /Users/drew/.cargo/git/checkouts/polkadot-sdk-cff69157b985ed76/88c32501/bridges/primitives/header-chain/src/justification/verification/optimizer.rs:134:21 | 134 | extra_precommits: vec![], | ^^^ | help: consider importing one of these items | 19 + use scale_info::prelude::vec; | 19 + use sp_std::vec; | error: cannot find macro `vec` in this scope --> /Users/drew/.cargo/git/checkouts/polkadot-sdk-cff69157b985ed76/88c32501 /bridges/primitives/header-chain/src/justification/verification/equivocation.rs:89:27 | 89 | let mut equivocations = vec![]; | ^^^ | help: consider importing one of these items | 19 + use scale_info::prelude::vec; | 19 + use sp_std::vec; ``` --------- Co-authored-by: Bastian Köcher <[email protected]> Co-authored-by: Serban Iorga <[email protected]> Co-authored-by: command-bot <> Co-authored-by: Adrian Catangiu <[email protected]>