Bump npm from 6.13.2 to 6.13.4

Bumps [npm](https://github.com/npm/cli) from 6.13.2 to 6.13.4.
- [Release notes](https://github.com/npm/cli/releases)
- [Changelog](https://github.com/npm/cli/blob/latest/CHANGELOG.md)
- [Commits](npm/cli@v6.13.2...v6.13.4)

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

Author: dependabot[bot]

package-lock.json

@@ -39,7 +39,7 @@
     "moment": "^2.24.0",
     "mustache": "^3.1.0",
     "node-color-log": "^2.2.0",
-    "npm": "^6.13.2",
+    "npm": "^6.13.4",
     "pemtools": "^0.4.7",
     "prismjs": "^1.17.1",
     "randomatic": "^3.0.0",