[ci] Roll pinned nightly toolchain (#1012)

Author: google-pr-creation-bot

Cargo.toml

@@ -44,7 +44,7 @@ zerocopy-panic-in-const = "1.57.0"
 [package.metadata.ci]
 # The versions of the stable and nightly compiler toolchains to use in CI.
 pinned-stable = "1.76.0"
-pinned-nightly = "nightly-2024-03-02"
+pinned-nightly = "nightly-2024-03-03"
 
 [package.metadata.docs.rs]
 all-features = true