Add cargo-args for building with core std

Author: swgiacomelli

Cargo.toml

@@ -79,6 +79,7 @@ critical-section = { version = "1.2", features = ["std"] }
 default-target = "xtensa-esp32-none-elf"
 features = ["smoltcp", "critical-section", "async", "embassy-net", "log", "defmt"]
 rustdoc-args = ["--cfg", "docsrs"]
+cargo-args = ["-Z", "build-std=core"]
 
 # =============================================================================
 # Integration Test Dependencies (only needed when building for target hardware)