deps: Update to latest modules.

[davecgh]

This updates the direct module dependencies as follows:

• decred.org/dcrwallet/v4@v4.0.0
• github.com/decred/dcrd/dcrutil/v4@v4.0.2
• github.com/decred/dcrd/rpc/jsonrpc/types/v4@v4.2.0

It also updates the indirect module dependencies as follows:

• github.com/decred/dcrd/dcrec/secp256k1/v4@v4.3.0
• github.com/decred/dcrd/txscript/v4@v4.1.1
• github.com/decred/dcrd/wire@v1.7.0
• github.com/klauspost/cpuid/v2@v2.2.5
• golang.org/x/sys@v0.20.0
• lukechampine.com/blake3@v1.3.0

This allows support for the new mix related chain server RPC methods:

• getmixpairrequests
• sendrawmixmessage

It also adds support for a new wallet RPC method:

• spendoutputs

[davecgh]

Updated the description accordingly.