wip: add some workflows for backporting, semver, and publishing

.github/workflows/backport.yml

@@ -0,0 +1,24 @@
+# Attempt to backport a merged pull request to the latest stable release
+#
+# If the backported PR is succesfully merged
+
+name: Backport merged pull request
+on:
+  pull_request_target:
+    types: [closed]
+
+permissions:
+  contents: write # so it can comment
+  pull-requests: write # so it can create pull requests
+
+jobs:
+  backport:
+    name: Backport pull request
+    runs-on: ubuntu-latest
+
+    # Don't run on closed unmerged pull requests
+    if: github.event.pull_request.merged
+    steps:
+      - uses: actions/checkout@v4
+      - name: Create backport pull requests
+        uses: korthout/backport-action@v2