Add new and transferred issues to project

When a new issue is created or an issue is transferred
from another project, we add the issue to the Spectre.Console project
(https://github.com/orgs/spectreconsole/projects/1).

.github/workflows/backlog.yaml

@@ -0,0 +1,18 @@
+# yaml-language-server: $schema=https://json.schemastore.org/github-workflow.json
+name: Add issues/PRs to backlog automatically
+
+on:
+  issues:
+    types:
+      - opened
+      - transferred
+
+jobs:
+  add-to-project:
+    name: Add issue to backlog
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/add-to-project@main
+        with:
+          project-url: https://github.com/orgs/spectreconsole/projects/1
+          github-token: ${{ secrets.PROJECT_TOKEN }}