ENH/CI: add mypy config, and CI workflow (#2066)

.github/workflows/typing.yaml

@@ -0,0 +1,46 @@
+name: "Typing Check"
+
+on:
+  pull_request:
+    paths:
+      - ".github/workflows/typing.yaml"
+      - "src/**"
+      - "pyproject.toml"
+  push:
+    branches:
+      - main
+      - develop
+      - release/\d{4}.\d{1,2}.\d{1,2}
+    paths:
+      - ".github/workflows/typing.yaml"
+      - "src/**"
+      - "pyproject.toml"
+
+jobs:
+  typing-check:
+    runs-on: ubuntu-latest
+    concurrency:
+      group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+      cancel-in-progress: true
+    steps:
+      - name: "Checkout Repository"
+        uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+
+      - name: Setup Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: "3.11"
+          cache: "pip"
+
+      - name: Install Nebari and type stubs
+        run: |
+          python --version
+          pip install -e .[dev]
+          pip install types-Pygments types-requests types-six
+
+      - name: Run MyPy
+        continue-on-error: true
+        run: |
+          mypy

pyproject.toml

@@ -78,6 +78,7 @@ dependencies = [
 [project.optional-dependencies]
 dev = [
     "black==22.3.0",
+    "mypy==1.6.1",
     "dask-gateway",
     "diagrams",
     "python-dotenv",
@@ -106,6 +107,34 @@ Source = "https://github.com/nebari-dev/nebari"
 [project.scripts]
 nebari = "nebari.__main__:main"
 
+[tool.mypy]
+warn_return_any = true
+warn_unused_configs = true
+files = [
+    "src/_nebari",
+    "src/nebari",
+]
+exclude = [
+    "src/_nebari/stages/kubernetes_services/template" # skip traitlets configuration files
+]
+
+[[tool.mypy.overrides]]
+module = [
+    "auth0.authentication",
+    "auth0.management",
+    "CloudFlare",
+    "kubernetes",
+    "kubernetes.client",
+    "kubernetes.config",
+    "kubernetes.client.rest",
+    "kubernetes.client.exceptions",
+    "keycloak",
+    "keycloak.exceptions",
+    "boto3",
+    "botocore.exceptions",
+]
+ignore_missing_imports = true
+
 [tool.ruff]
 select = [
     "E",