Use erlef/setup-beam, bump gha versions (#76)

Remove extra redirection. See https://github.com/erlef/setup-beam/issues/20

.github/workflows/elixir.yml

@@ -13,16 +13,16 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
 
     - name: Set up Elixir
-      uses: erlef/setup-elixir@885971a72ed1f9240973bd92ab57af8c1aa68f24
+      uses: erlef/setup-beam@v1
       with:
         elixir-version: '1.12.3'
         otp-version: '24'
 
     - name: Restore dependencies cache
-      uses: actions/cache@v2
+      uses: actions/cache@v3
       with:
         path: deps
         key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}

.github/workflows/update-instances.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Install dependencies
       run: sudo apt-get install -y jq dnsutils