ci: update github actions workflow

.github/workflows/ci.yml

@@ -1,24 +1,43 @@
 name: CI
 
 on:
+  workflow_dispatch:
   push:
+    branches:
+      - main
+  pull_request:
 
 jobs:
-  build:
-    name: build
+  dependabot:
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+    if: github.ref != 'refs/heads/main' && github.actor == 'dependabot[bot]'
     steps:
-      - uses: actions/checkout@v3
+      - name: Dependabot PR merge
+        run: gh pr merge --auto --squash "$PR_URL"
+        env:
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Set up Python
-        uses: actions/setup-python@v4
+  build:
+    runs-on: ubuntu-latest
+    if: github.ref == 'refs/heads/main'
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
         with:
           python-version: "3.12"
+          cache: "pipenv"
+
+      - name: Install pipenv
+        run: |
+          curl https://raw.githubusercontent.com/pypa/pipenv/master/get-pipenv.py | python
 
-      - name: Install pipenv and project dependencies
+      - name: Install Python dependencies
         run: |
-          python -m pip install --upgrade pipenv
-          pipenv install --dev --pre
+          pipenv install --deploy --dev
 
       - name: Run code linter and formatter
         run: |