Default to publishing with provenance in npm publish workflow

Pre-requisites

[ ] Prior to submitting a new workflow, please apply to join the GitHub Technology Partner Program: partner.github.com/apply.

Please note that at this time we are only accepting new starter workflows for Code Scanning. Updates to existing starter workflows are fine.

Tasks

For all workflows, the workflow:

[x] Should be contained in a .yml file with the language or platform as its filename, in lower, kebab-cased format (for example, docker-image.yml). Special characters should be removed or replaced with words as appropriate (for example, "dotnet" instead of ".NET").
[x] Should use sentence case for the names of workflows and steps (for example, "Run tests").
[x] Should be named only by the name of the language or platform (for example, "Go", not "Go CI" or "Go Build").
[x] Should include comments in the workflow for any parts that are not obvious or could use clarification.
[x] Should specify least privileged permissions for GITHUB_TOKEN so that the workflow runs successfully.

For CI workflows, the workflow:

[x] Should be preserved under the ci directory.
[x] Should include a matching ci/properties/*.properties.json file (for example, ci/properties/docker-publish.properties.json).
[x] Should run on push to branches: [ $default-branch ] and pull_request to branches: [ $default-branch ].
[x] Packaging workflows should run on release with types: [ created ].
[x] Publishing workflows should have a filename that is the name of the language or platform, in lower case, followed by "-publish" (for example, docker-publish.yml).

Some general notes:

[x] This workflow must only use actions that are produced by GitHub, in the actions organization, or
[x] This workflow must only use actions that are produced by the language or ecosystem that the workflow supports. These actions must be published to the GitHub Marketplace. We require that these actions be referenced using the full 40 character hash of the action's commit instead of a tag. Additionally, workflows must include the following comment at the top of the workflow file:
```
# This workflow uses actions that are not certified by GitHub.
# They are provided by a third-party and are governed by
# separate terms of service, privacy policy, and support
# documentation.
```
[ ] Automation and CI workflows should not send data to any 3rd party service except for the purposes of installing dependencies.
[x] Automation and CI workflows cannot be dependent on a paid service or product.

Description

Update the npm-publish.yml starter workflow to publish with provenance to encourage users publishing to npm to use provenance. The implementation is based on (but improved compared to) the example found at https://docs.npmjs.com/generating-provenance-statements (accessed March 20, 2024, copied below). A prerequisite for this is upgrading Node.js to v20 because it ships with an npm version that supports the --provenance flag.

I can see this being in violation with "Automation and CI workflows should not send data to any 3rd party service except for the purposes of installing dependencies." which is why I didn't mark it. If it is, feel free to reject this.

Part of the changes here are covered by #2269

workflow from npm docs

```yml name: Publish Package to npmjs on: release: types: [created] jobs: build: runs-on: ubuntu-latest permissions: contents: read id-token: write steps: - uses: actions/checkout@v3 - uses: actions/setup-node@v3 with: node-version: '18.x' registry-url: 'https://registry.npmjs.org' - run: npm install -g npm - run: npm ci - run: npm publish --provenance --access public env: NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }} ```

actions / starter-workflows