Increase MSRV to 1.81.0

Author: alamb

Cargo.toml

@@ -65,7 +65,7 @@ homepage = "https://datafusion.apache.org"
 license = "Apache-2.0"
 readme = "README.md"
 repository = "https://github.com/apache/datafusion"
-rust-version = "1.80.1"
+rust-version = "1.81.0"
 version = "44.0.0"
 
 [workspace.dependencies]