ci: add pull request validation workflow

.github/workflows/pr.yml

@@ -0,0 +1,42 @@
+name: PR
+
+on: [pull_request]
+
+jobs:
+  Validate:
+    runs-on: ubuntu-latest
+    name: Validate OTP ${{matrix.otp}} / Elixir ${{matrix.elixir}}
+    strategy:
+      matrix:
+        elixir:
+          - 1.15
+        otp:
+          - 26.1
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up Elixir
+      uses: erlef/setup-beam@v1
+      with:
+        elixir-version: ${{ matrix.elixir }}
+        otp-version: ${{ matrix.otp }}
+    - uses: actions/cache@v3
+      with:
+        path: |
+          deps
+          _build
+        key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }}
+        restore-keys: |
+          ${{ runner.os }}-mix-
+    - name: Install Dependencies
+      run: mix deps.get
+    - name: Check Format
+      run: mix format --check-formatted
+    - name: Compile
+      run: mix compile --all-warnings --warnings-as-errors
+    - name: Test
+      run: mix test
+    
+        
+
+
+