update to nightly-2025-03-03

https://github.com/Rahix/avr-hal/pull/634

Cargo.toml

@@ -18,15 +18,9 @@ calc-math = { path = "../calc-math" }
 
 [dependencies.arduino-hal]
 git = "https://github.com/rahix/avr-hal"
-rev = "3c089795cadbbc7fa83f45958128689fee7ba1e4"
+rev = "a1d727e58d73fa4bf41e8113337abb824371ca5d"
 features = ["arduino-nano"]
 
-# The latest releases of `proc-macro2` do not support the rust toolchain that
-# we use.  Thus, we must fix this dependency to an older version where our
-# toolchain is still supported.  See https://github.com/Rahix/avr-hal/issues/537
-[build-dependencies.proc-macro2]
-version = "=1.0.79"
-
 # Configure the build for minimal size - AVRs have very little program memory
 [profile.dev]
 panic = "abort"