Update to base64 0.22.1

[AaronDewes]

This is just simple dependency update to avoid people having duplicate (old) versions of base64 in their dependency tree if they use this crate.

[apoelstra]

I think this is fine, but can you update the included lockfiles Cargo-minimal.lock and Cargo-recent.lock?

You can run just update-lock-files to do this.

[tcharding]

Verified that this is the same version we depend on in bitcoin.

[tcharding]

I rebase on master, updated the lock files, and force pushed to your branch. Hope you don't mind. You can use git range-diff aeaf57c...@ to see what changes I pushed and you can verify aeaf57c is your patch by looking at the original push above. You are still the patch author, and I don't know where github gets the data to include my avatar on the patch.

Thanks for the PR!! Appreciate it.