Update dependency rust-lang/rust to v1.85.0

Author: renovate[bot]

charmcraft.yaml

@@ -75,7 +75,7 @@ parts:
       # rpds-py (Python package) >=0.19.0 requires rustc >=1.76, which is not available in the
       # Ubuntu 22.04 archive. Install rustc and cargo using rustup instead of the Ubuntu archive
       rustup set profile minimal
-      rustup default 1.84.1  # renovate: charmcraft-rust-latest
+      rustup default 1.85.0  # renovate: charmcraft-rust-latest
 
       craftctl default
       # Include requirements.txt in *.charm artifact for easier debugging