ci: Enable automated versioning and NPM publishing

From now on, commits must follow Conventional Commits, and `release-please` Github Action will maintain a CHANGELOG file and an automated PR to release versions with the latest changes. Once an automated PRbumps the version, it will also publish the lpackage to the NPM registry.

.github/workflows/release.yml

@@ -0,0 +1,30 @@
+name: release-please
+on:
+  push:
+    branches:
+      - master
+jobs:
+  release-please:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: GoogleCloudPlatform/release-please-action@v2
+        id: release
+        with:
+          release-type: node
+          package-name: ${{ github.event.repository.name }}
+      # The logic below handles the npm publication:
+      - uses: actions/checkout@v2
+        # these if statements ensure that a publication only occurs when
+        # a new release is created:
+        if: ${{ steps.release.outputs.release_created }}
+      - uses: actions/setup-node@v1
+        if: ${{ steps.release.outputs.release_created }}
+        with:
+          node-version: ${{ matrix.node-version }}
+          registry-url: 'https://registry.npmjs.org'
+      - run: npm ci
+        if: ${{ steps.release.outputs.release_created }}
+      - run: npm publish
+        if: ${{ steps.release.outputs.release_created }}
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}