Create GitHub Action for FlowCrafter

FlowCrafter can now be run automatically as a GitHub Action. When it
detects changes to the workflows, it automatically creates a pull
request to update them.

.github/workflows/flowcrafter.yml

@@ -0,0 +1,24 @@
+---
+name: FlowCrafter
+
+"on":
+  pull_request:
+  schedule:
+    - cron: "0 0 * * *"
+  workflow_dispatch:
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  update:
+    name: Update
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Run FlowCrafter
+        uses: ./

.yamllint.yml

@@ -5,3 +5,4 @@ rules:
   line-length:
     ignore: |
       .github/workflows/*
+      action.yml

action.yml

@@ -0,0 +1,45 @@
+---
+name: FlowCrafter
+description: Run FlowCrafter and update the GitHub Actions
+
+runs:
+  using: "composite"
+  steps:
+    - name: Install FlowCrafter
+      shell: bash
+      run: "curl --proto '=https' --tlsv1.2 -LsSf https://github.com/jdno/flowcrafter/releases/download/v0.3.0/flowcrafter-installer.sh | sh"
+
+    - name: Print FlowCrafter version
+      shell: bash
+      run: 'echo "Using FlowCrafter v$(flowcrafter --version)"'
+
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: flowcrafter update
+      shell: bash
+      run: "flowcrafter update"
+
+    - name: Check if workflows changed
+      id: check
+      shell: bash
+      run: |
+        if git diff --cached --exit-code --quiet; then
+          echo 'No changes detected'
+          echo "changed=false" >> $GITHUB_OUTPUT
+        else
+          echo 'Changes detected'
+          echo "changed=true" >> $GITHUB_OUTPUT
+        fi
+
+    - name: Create pull request
+      uses: peter-evans/create-pull-request@v5
+      if: steps.check.outputs.changed == 'true' && github.event_name != 'push' && github.event_name != 'pull_request'
+      with:
+        add-paths: ".github/workflows"
+        branch: "flowcrafter/update"
+        commit-message: "Update GitHub Actions"
+        title: "Update GitHub Actions"
+        body: |
+          This pull request was automatically created by FlowCrafter after
+          running `flowcrafter update` on the repository.