ci(docs): add action for auto-generating the documentation

Author: kangasta

.github/workflows/docs.yml

@@ -0,0 +1,35 @@
+name: Documentation
+
+on:
+  pull_request:
+    types:
+    - closed
+    branches:
+    - main
+    - test-docs-generator # for testing
+
+jobs:
+  update:
+    name: Update
+    if: github.event.pull_request.merged == true
+    runs-on: ubuntu-latest
+    steps:
+    - name: Setup Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: "1.17"
+    - name: Checkout
+      uses: actions/checkout@v2
+    - name: Generate documentation
+      run: make generate
+    - name: Create PR for docs update
+      uses: peter-evans/create-pull-request@v4
+      with:
+        add-paths: docs/
+        branch: chore/update-docs
+        commit-message: "chore(docs): update documentation for #${{ github.event.number }}"
+        committer: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
+        reviewers: ${{ github.actor }}
+        title: Update documentation
+        body: "This is an automatically created PR. Changes were created by running `make docs` after merging #${{ github.event.number }} (${{ github.sha }})."
+        base: ${{ github.event.pull_request.base.ref }}