[ci] Roll pinned stable toolchain (#2454)

Author: google-pr-creation-bot

Cargo.toml

@@ -59,7 +59,7 @@ zerocopy-panic-in-const-and-vec-try-reserve-1-57-0 = "1.57.0"
 
 [package.metadata.ci]
 # The versions of the stable and nightly compiler toolchains to use in CI.
-pinned-stable = "1.85.0"
+pinned-stable = "1.85.1"
 pinned-nightly = "nightly-2025-03-17"
 
 [package.metadata.docs.rs]