mixing: Prepare v0.4.2.

This updates the mixing module dependencies and serves as a base for
mixing/v0.4.2.

The updated direct dependencies in this commit are as follows:

- github.com/decred/dcrd/crypto/blake256@v1.1.0

The full list of updated direct dependencies since the previous
mixing/v0.4.1 release are the same as above.

Finally, all modules in the repository are tidied to ensure they are
updated to use the latest versions hoisted forward as a result.

mixing/go.mod

@@ -9,7 +9,7 @@ require (
 	github.com/decred/dcrd/chaincfg/chainhash v1.0.4
 	github.com/decred/dcrd/chaincfg/v3 v3.2.1
 	github.com/decred/dcrd/container/lru v1.0.0
-	github.com/decred/dcrd/crypto/blake256 v1.0.1
+	github.com/decred/dcrd/crypto/blake256 v1.1.0
 	github.com/decred/dcrd/crypto/rand v1.0.0
 	github.com/decred/dcrd/dcrec v1.0.1
 	github.com/decred/dcrd/dcrec/secp256k1/v4 v4.3.0

mixing/go.sum

@@ -16,8 +16,8 @@ github.com/decred/dcrd/chaincfg/v3 v3.2.1 h1:x9zKJaU24WAKbxAR1UyFKHlM3oJgP0H9Lod
 github.com/decred/dcrd/chaincfg/v3 v3.2.1/go.mod h1:SDCWDtY7BLj0leXc9FuoA1YjSVKyCIBVAyxwZn6+sXc=
 github.com/decred/dcrd/container/lru v1.0.0 h1:7foQymtbu18aQWYiY9RnNIeE+kvpiN+fiBQ3+viyJjI=
 github.com/decred/dcrd/container/lru v1.0.0/go.mod h1:vlPwj0l+IzAHhQSsbgQnJgO5Cte78+yI065V+Mc5PRQ=
-github.com/decred/dcrd/crypto/blake256 v1.0.1 h1:7PltbUIQB7u/FfZ39+DGa/ShuMyJ5ilcvdfma9wOH6Y=
-github.com/decred/dcrd/crypto/blake256 v1.0.1/go.mod h1:2OfgNZ5wDpcsFmHmCK5gZTPcCXqlm2ArzUIkw9czNJo=
+github.com/decred/dcrd/crypto/blake256 v1.1.0 h1:zPMNGQCm0g4QTY27fOCorQW7EryeQ/U0x++OzVrdms8=
+github.com/decred/dcrd/crypto/blake256 v1.1.0/go.mod h1:2OfgNZ5wDpcsFmHmCK5gZTPcCXqlm2ArzUIkw9czNJo=
 github.com/decred/dcrd/crypto/rand v1.0.0 h1:Ah9Asl36OZt09sGSMbJZuL1HfwGdlC38q/ZUeLDVKRg=
 github.com/decred/dcrd/crypto/rand v1.0.0/go.mod h1:coa7BbxSTiKH6esi257plGfMFYuGL4MTbQlLYnOdzpE=
 github.com/decred/dcrd/crypto/ripemd160 v1.0.2 h1:TvGTmUBHDU75OHro9ojPLK+Yv7gDl2hnUvRocRCjsys=