Add automatic snapshots update workflow (#1939)

.github/workflows/update-snapshots.yml

@@ -0,0 +1,52 @@
+name: Update snapshots
+
+on:
+  push:
+    branches:
+      - dev
+  workflow_dispatch:
+
+jobs:
+  update-snapshots:
+    name: Update snapshots
+    if: github.repository == 'vacanza/python-holidays'
+    permissions:
+      contents: write
+      pull-requests: write
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          cache: pip
+          cache-dependency-path: |
+            requirements/build.txt
+            requirements/dev.txt
+          check-latest: true
+          python-version: '3.12'
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install -r requirements/build.txt
+          python -m pip install -r requirements/dev.txt
+          make package
+          python -m pip install dist/*.tar.gz
+
+      - name: Generate snapshots
+        run: |
+          make snapshot
+
+      - uses: peter-evans/create-pull-request@v6.1.0
+        with:
+          base: dev
+          body: Automatically generated snapshots update.
+          branch: update-snapshots
+          commit-message: 'Update snapshots [skip ci]'
+          committer: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
+          delete-branch: true
+          title: 'chore: Update snapshots'
+          token: ${{ github.token }}