chore: patch sigma-proofs and spongefish to their mu/draft-v3 branches

Cargo.toml

@@ -26,5 +26,7 @@ dump = [ "sigma-compiler-derive/dump" ]
 [patch.crates-io]
 sigma-compiler-derive = { path = "sigma-compiler-derive" }
 sigma-compiler-core = { path = "sigma-compiler-core" }
-# sigma-proofs = { path = "../sigma-proofs" }
-# spongefish = { path = "../spongefish/spongefish" }
+# Until the draft-v3 line of both crates is released, take them from the
+# branches the rewrite lives on.
+sigma-proofs = { git = "https://github.com/sigma-rs/sigma-proofs", branch = "mu/draft-v3" }
+spongefish = { git = "https://github.com/arkworks-rs/spongefish", branch = "mu/draft-v3" }