Bump lodash from 4.17.11 to 4.17.21

Bumps [lodash](https://github.com/lodash/lodash) from 4.17.11 to 4.17.21.
- [Release notes](https://github.com/lodash/lodash/releases)
- [Commits](lodash/lodash@4.17.11...4.17.21)

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

Author: dependabot[bot]

package-lock.json

@@ -24,7 +24,7 @@
     "install": "^0.13.0",
     "linkify-html": "^3.0.5",
     "linkifyjs": "^3.0.5",
-    "lodash": ">=4.6.2",
+    "lodash": ">=4.17.21",
     "marked": "^2.0.3",
     "moment": "^2.24.0",
     "new-github-issue-url": "^1.0.0",