Critical vulnerability in `ismp-grandpa` <v15.0.1

Hyperbridge is a hyper-scalable coprocessor for verifiable, cross-chain interoperability. A critical vulnerability was discovered in the ismp-grandpa crate, that allowed a malicious prover easily convince the verifier of the finality of arbitrary headers. This could be used to steal funds or compromise other kinds of cross-chain applications. This vulnerability is fixed in 15.0.1.