Cargo: no target_arch = wasm32 for native-certs dep

The `rustls-native-certs` crate doesn't support WASM (there's no native
cert bundle or platform verifier). The existing conditional dependency
import in `Cargo.toml` allowed the `unix` platform family that may
include a wasm target arch target. This commit updates it to exclude
these targets.

rustls-platform-verifier/Cargo.toml

@@ -35,7 +35,7 @@ base64 = { version = "0.21", optional = true } # Only used when the `cert-loggin
 jni = { version = "0.19", default-features = false, optional = true } # Only used during doc generation
 once_cell = "1.9"
 
-[target.'cfg(all(unix, not(target_os = "android"), not(target_os = "macos"), not(target_os = "ios"), not(target_os = "tvos")))'.dependencies]
+[target.'cfg(all(unix, not(target_os = "android"), not(target_os = "macos"), not(target_os = "ios"), not(target_os = "tvos"), not(target_arch = "wasm32")))'.dependencies]
 rustls-native-certs = "0.7"
 webpki = { package = "rustls-webpki", version = "0.102", default-features = false }