Use edition 2021 in CI

jamwaffles · jamwaffles · commit b5cf3d755b35 · 2022-08-14T11:40:59.000+01:00
diff --git a/.circleci/config.yml b/.circleci/config.yml
@@ -1,6 +1,6 @@
 target_steps: &target_steps
   docker:
-    - image: cimg/rust:1.51.0
+    - image: cimg/rust:1.56.0
   steps:
     - checkout
     - restore_cache:
