ci: Switch to GitHub actions for CI (#44)

* Switch to GitHub actions for CI

* More cautious dep updates

* Update based on review feedback

Author: microbit-matt-hillsdon

.circleci/config.yml

@@ -0,0 +1,26 @@
+name: build
+on:
+  release:
+    types: [created]
+  push:
+    branches:
+      - '**'
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20.x'
+          registry-url: 'https://registry.npmjs.org'
+          cache: npm
+      - run: npm ci
+      - run: npm run test:coverage
+      - run: npm run build
+      - run: npm publish
+        if: github.event_name == 'release' && github.event.action == 'created'
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}