Raise compiler version required for preserve_order feature to 1.82

Required since version 2.12.0 of indexmap.

Author: dtolnay

.github/workflows/ci.yml

@@ -44,7 +44,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        rust: [beta, 1.65.0, 1.61.0]
+        rust: [beta, 1.82.0, 1.61.0]
         os: [ubuntu]
         include:
           - rust: stable