chore: make ethers-etherscan compile for wasm32 (#1403)

Cargo.lock

@@ -1288,6 +1288,7 @@ version = "0.13.0"
 dependencies = [
  "ethers-core",
  "ethers-solc",
+ "getrandom 0.2.7",
  "reqwest",
  "semver",
  "serde",

ethers-etherscan/Cargo.toml

@@ -23,6 +23,10 @@ thiserror = "1.0"
 tracing = "0.1.35"
 semver = "1.0.10"
 
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+# NOTE: this enables wasm compatibility for getrandom indirectly
+getrandom = { version = "0.2", features = ["js"] }
+
 [dev-dependencies]
 tempfile = "3.3.0"
 tokio = { version = "1.18", features = ["macros", "rt-multi-thread", "time"] }