Blast API shutting down after Oct 31

Hey,

[Blast API](https://blastapi.io/) is shutting down after Oct 31, 2025. You might want to update [this reference](https://github.com/berachain/guides/blob/main/apps/erpc-proxy-caching/README.md#L24) to another RPC provider, for example [Chainstack](https://chainstack.com).