all: fix clippy lints for rust 1.65

.github/workflows/rust.yaml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v2
     - name: Format
       run: cargo fmt --all -- --check
     - name: Lint

aoc2020/src/day16.rs

@@ -223,7 +223,7 @@ mod tests {
 
         let matches = assign_field_positions(fields, tickets);
 
-        let expected = ["row", "class", "seat"]
+        let expected = (&["row", "class", "seat"])
             .iter()
             .copied()
             .enumerate()