Bump proc-macro2 from 1.0.50 to 1.0.51 (#812)

Bumps [proc-macro2](https://github.com/dtolnay/proc-macro2) from 1.0.50 to 1.0.51.
- [Release notes](https://github.com/dtolnay/proc-macro2/releases)
- [Commits](https://github.com/dtolnay/proc-macro2/compare/1.0.50...1.0.51)

---
updated-dependencies:
- dependency-name: proc-macro2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: James Wilson <james@jsdw.me>

Cargo.lock

@@ -2266,9 +2266,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.50"
+version = "1.0.51"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6ef7d57beacfaf2d8aee5937dab7b7f28de3cb8b1828479bb5de2a7106f2bae2"
+checksum = "5d727cae5b39d21da60fa540906919ad737832fe0b1c165da3a34d6548c849d6"
 dependencies = [
  "unicode-ident",
 ]

codegen/Cargo.toml

@@ -16,7 +16,7 @@ codec = { package = "parity-scale-codec", version = "3.0.0", default-features =
 darling = "0.14.0"
 frame-metadata = "15.0.0"
 heck = "0.4.1"
-proc-macro2 = "1.0.24"
+proc-macro2 = "1.0.51"
 proc-macro-error = "1.0.4"
 quote = "1.0.8"
 syn = "1.0.58"