fix: bump setup-beam to v1.15.4 (#26)

fix: bump setup-beam to v1.15.4

Author: khvn26

.github/workflows/test_format_dialyze.yml

@@ -10,15 +10,15 @@ jobs:
   build:
 
     name: Build and test
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-20.04
 
     steps:
     - name: Checkout
       uses: actions/checkout@v2
       with:
         submodules: 'true'
     - name: Set up Elixir
-      uses: erlef/setup-beam@988e02bfe678367a02564f65ca2e37726dc0268f
+      uses: erlef/setup-beam@v1.15.4
       with:
         elixir-version: '1.12.3'
         otp-version: '24.1'