chore(deps): bump proc-macro2 from 1.0.29 to 1.0.30 (#504)

Bumps [proc-macro2](https://github.com/alexcrichton/proc-macro2) from 1.0.29 to 1.0.30.
- [Release notes](https://github.com/alexcrichton/proc-macro2/releases)
- [Commits](dtolnay/proc-macro2@1.0.29...1.0.30)

---
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>

ethers-core/Cargo.toml

@@ -37,7 +37,7 @@ once_cell = "1.8.0"
 convert_case = { version = "0.4.0", optional = true }
 syn = { version = "1.0.80", optional = true }
 quote = { version = "1.0.9", optional = true }
-proc-macro2 = { version = "1.0.29", optional = true }
+proc-macro2 = { version = "1.0.30", optional = true }
 
 [target.'cfg(not(target_arch = "wasm32"))'.dependencies]
 # async