Bump GHA versions to fix CI failures

Author: fhunleth

.github/workflows/elixir.yml

@@ -18,7 +18,7 @@ jobs:
         otp: [23.3]
     steps:
     - name: checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
       with:
         fetch-depth: 0
     - name: setup
@@ -27,7 +27,7 @@ jobs:
         elixir-version: ${{ matrix.elixir }}
         otp-version: ${{ matrix.otp }}
     - name: Retrieve Cached Dependencies
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       id: mix-cache
       with:
         path: |
@@ -54,7 +54,7 @@ jobs:
         elixir: [1.11]
         otp: [23.3]
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 0
     - name: Setup elixir
@@ -63,7 +63,7 @@ jobs:
         elixir-version: ${{ matrix.elixir }}
         otp-version: ${{ matrix.otp }}
     - name: Retrieve Cached Dependencies
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       id: mix-cache
       with:
         path: |
@@ -85,15 +85,15 @@ jobs:
         elixir: [1.11]
         otp: [23.3]
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
       with:
         fetch-depth: 0
     - uses: erlef/setup-beam@v1
       with:
         elixir-version: ${{ matrix.elixir }}
         otp-version: ${{ matrix.otp }}
     - name: Retrieve Cached Dependencies
-      uses: actions/cache@v2
+      uses: actions/cache@v4
       id: mix-cache
       with:
         path: |