Bump MSRV in CI

Author: meithecatte

.github/workflows/rust.yml

@@ -10,7 +10,7 @@ jobs:
           - rust: nightly
           - rust: stable
             extra-test-opts: -- --skip ui
-          - rust: 1.41.1
+          - rust: 1.56
             extra-test-opts: -- --skip ui
     runs-on: ubuntu-latest