Update npm scripts to use node:latest instead of node:16.

Author: DavidAnson

package.json

@@ -29,8 +29,8 @@
     "build-docker-image": "VERSION=$(node -e \"process.stdout.write(require('./package.json').version)\") && docker build -t davidanson/markdownlint-cli2:v$VERSION -f docker/Dockerfile --label org.opencontainers.image.version=v$VERSION .",
     "build-docker-image-rules": "VERSION=$(node -e \"process.stdout.write(require('./package.json').version)\") && docker build -t davidanson/markdownlint-cli2-rules:v$VERSION -f docker/Dockerfile-rules --build-arg VERSION=v$VERSION --label org.opencontainers.image.version=v$VERSION .",
     "ci": "npm-run-all --continue-on-error --parallel test-cover lint",
-    "docker-npm-install": "docker run --rm --tty --name npm-install --volume $PWD:/home/workdir --workdir /home/workdir --user node node:16 npm install",
-    "docker-npm-run-upgrade": "docker run --rm --tty --name npm-run-upgrade --volume $PWD:/home/workdir --workdir /home/workdir --user node node:16 npm run upgrade",
+    "docker-npm-install": "docker run --rm --tty --name npm-install --volume $PWD:/home/workdir --workdir /home/workdir --user node node:latest npm install",
+    "docker-npm-run-upgrade": "docker run --rm --tty --name npm-run-upgrade --volume $PWD:/home/workdir --workdir /home/workdir --user node node:latest npm run upgrade",
     "lint": "eslint --max-warnings 0 .",
     "lint-dockerfile": "docker run --rm -i hadolint/hadolint:latest-alpine < docker/Dockerfile",
     "lint-watch": "git ls-files | entr npm run lint",