Bump express from 4.17.1 to 4.17.3

Bumps [express](https://github.com/expressjs/express) from 4.17.1 to 4.17.3.
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/master/History.md)
- [Commits](expressjs/express@4.17.1...4.17.3)

---
updated-dependencies:
- dependency-name: express
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

package.json

@@ -21,7 +21,7 @@
     "@vuepress/plugin-back-to-top": "^1.8.2",
     "@vuepress/plugin-medium-zoom": "^1.8.2",
     "applicationinsights": "^2.1.5",
-    "express": "^4.17.1"
+    "express": "^4.17.3"
   },
   "devDependencies": {
     "@vuepress/plugin-google-analytics": "^1.8.2",