chore: bump bignum version to v0.5.4 (#33)

* chore: bump bignum version to `v0.5.2`

* Update Nargo.toml

* Update Nargo.toml

Author: TomAFrench

Nargo.toml

@@ -5,5 +5,5 @@ authors = [""]
 compiler_version = ">=1.0.0"
 
 [dependencies]
-bignum = {tag = "v0.5.0", git = "https://github.com/noir-lang/noir-bignum"}
+bignum = {tag = "v0.5.4", git = "https://github.com/noir-lang/noir-bignum"}
 sort = {tag = "v0.2.2", git = "https://github.com/noir-lang/noir_sort"}