Use npm ci instead of npm install in release script

In order not to update the package-lock.json file during releases.

package.json

@@ -48,7 +48,7 @@
     "coverage": "nyc npm test",
     "lint": "eslint .",
     "docs": "jsdoc --configure .jsdocrc.js --destination docs --recurse README.md src && printf '%s' 'docs.openpgpjs.org' > docs/CNAME",
-    "preversion": "rm -rf dist docs node_modules && npm install && npm test",
+    "preversion": "rm -rf dist docs node_modules && npm ci && npm test",
     "version": "npm run docs && git add -A docs",
     "postversion": "git push && git push --tags && npm publish"
   },