update CI

Author: SteffenDE

.github/workflows/ci.yml

@@ -28,15 +28,15 @@ jobs:
 
     steps:
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     - name: Hex and Rebar setup
       run: |
         mix local.hex --force
         mix local.rebar --force
 
     - name: Restore deps and _build cache
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       with:
         path: |
           deps