auto-add issues triggered from main repo

This is a sibling commit for bookwyrm-social/bookwyrm#3363

These add a pair of GitHub Actions to create a new issue in the documentation repository when a PR with a `needs-docs` label is merged in the main repository.

1. In order to work, the related PR in the main repository will also need to be merged, as it triggers the job here, and the Bot set up as described in the PR in the main repository.

.github/ACTION_ISSUE_TEMPLATE.md

@@ -0,0 +1,11 @@
+---
+title: Document PR {{ payload.client_payload.number }} - {{ payload.client_payload.title }}
+---
+
+Documentation is needed for changes made in https://github.com/bookwyrm-social/bookwyrm/pull/{{ payload.client_payload.number }}
+
+Pull Request notes are below.
+
+---
+
+{{ payload.client_payload.body }}

.github/workflows/receive_docs_issues.yml

@@ -0,0 +1,16 @@
+name: Repository Dispatch
+on:
+  repository_dispatch:
+    types: [docs-needed]
+jobs:
+  create-issue:
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+    steps:
+      - uses: actions/checkout@v4
+      - uses: JasonEtco/create-an-issue@v2
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          filename: .github/ACTION_ISSUE_TEMPLATE.md