Update CI dependency versions.

Author: sunfishcode

.github/actions/install-rust/action.yml

@@ -8,5 +8,5 @@ inputs:
     default: 'stable'
 
 runs:
-  using: node16
+  using: node20
   main: 'main.js'

.github/workflows/main.yml

@@ -11,7 +11,7 @@ jobs:
     name: Rustfmt
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         submodules: true
     - uses: ./.github/actions/install-rust
@@ -34,7 +34,7 @@ jobs:
             rust: stable
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         submodules: true
     - uses: ./.github/actions/install-rust