Bump lodash from 4.17.11 to 4.17.19

Bumps [lodash](https://github.com/lodash/lodash) from 4.17.11 to 4.17.19.
- [Release notes](https://github.com/lodash/lodash/releases)
- [Commits](https://github.com/lodash/lodash/compare/4.17.11...4.17.19)

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

package.json

@@ -55,7 +55,7 @@
     "@observablehq/runtime": "4",
     "babel-plugin-transform-react-pure-class-to-function": "1.0.1",
     "babel-plugin-transform-react-remove-prop-types": "0.4.24",
-    "lodash": "4.17.11",
+    "lodash": "4.17.19",
     "prop-types": "15.7.2",
     "react": "16.8.6",
     "react-dom": "16.8.6",