Bump bootstrap from 4.1.1 to 4.3.1

Bumps [bootstrap](https://github.com/twbs/bootstrap) from 4.1.1 to 4.3.1.
- [Release notes](https://github.com/twbs/bootstrap/releases)
- [Commits](https://github.com/twbs/bootstrap/compare/v4.1.1...v4.3.1)

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

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

package-lock.json

@@ -1811,9 +1811,9 @@
       "integrity": "sha1-aN/1++YMUes3cl6p4+0xDcwed24="
     },
     "bootstrap": {
-      "version": "4.1.1",
-      "resolved": "https://registry.npmjs.org/bootstrap/-/bootstrap-4.1.1.tgz",
-      "integrity": "sha512-SpiDSOcbg4J/PjVSt4ny5eY6j74VbVSjROY4Fb/WIUXBV9cnb5luyR4KnPvNoXuGnBK1T+nJIWqRsvU3yP8Mcg=="
+      "version": "4.3.1",
+      "resolved": "https://registry.npmjs.org/bootstrap/-/bootstrap-4.3.1.tgz",
+      "integrity": "sha512-rXqOmH1VilAt2DyPzluTi2blhk17bO7ef+zLLPlWvG494pDxcM234pJ8wTc/6R40UWizAIIMgxjvxZg5kmsbag=="
     },
     "boxen": {
       "version": "0.6.0",

package.json

@@ -9,7 +9,7 @@
     "babel-loader": "8.0.1",
     "babel-preset-react-app": "^3.1.2",
     "babel-runtime": "6.23.0",
-    "bootstrap": "^4.1.1",
+    "bootstrap": "^4.3.1",
     "case-sensitive-paths-webpack-plugin": "2.1.2",
     "chalk": "1.1.3",
     "css-loader": "0.28.4",