ci: add automatic semver

Will need to supply personal access token as repo secret `RELEASE_PLEASE_TOKEN`

.github/workflows/release-please.yml

@@ -0,0 +1,25 @@
+name: Release Please
+
+on:
+  push:
+    branches:
+      - 'main'
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  release-please:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Release with release-please
+        uses: google-github-actions/release-please-action@v4
+        with:
+          # PAT with write access to the repository
+          token: ${{ secrets.RELEASE_PLEASE_TOKEN }}
+          # optional. customize path to release-please-config.json
+          config-file: release-please-config.json
+          # optional. customize path to .release-please-manifest.json
+          manifest-file: .release-please-manifest.json

.release-please-manifest.json

@@ -0,0 +1,3 @@
+{
+  ".": "3.8.0"
+}

release-please-config.json

@@ -0,0 +1,13 @@
+{
+  "packages": {
+    ".": {
+      "changelog-path": "CHANGELOG.md",
+      "release-type": "python",
+      "bump-minor-pre-major": false,
+      "bump-patch-for-minor-pre-major": false,
+      "draft": false,
+      "prerelease": false
+    }
+  },
+  "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json"
+}