feat(workflows): add linting workflow

.github/workflows/linting.yml

@@ -0,0 +1,47 @@
+name: referral-api
+
+on:
+  push:
+    branches:
+      - develop
+      - main
+  pull_request:
+    branches:
+      - develop
+      - main
+
+jobs:
+  isort:
+    name: Sorting
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Install Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: "3.9"
+
+      - name: Install isort
+        run: pip install isort
+
+      - name: Run isort
+        run: isort --check src
+
+
+  flake8:
+    name: Linter
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Install Python
+        uses: actions/setup-python@v2
+        with:
+          python-version: "3.9"
+
+      - name: Install flake8
+        run: pip install flake8
+
+      - name: Run flake8
+        run: flake8 src --count --statistics --show-source