Bump bootstrap from 4.0.0 to 4.3.1

Bumps [bootstrap](https://github.com/twbs/bootstrap) from 4.0.0 to 4.3.1.
- [Release notes](https://github.com/twbs/bootstrap/releases)
- [Commits](https://github.com/twbs/bootstrap/compare/v4.0.0...v4.3.1)

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

package.json

@@ -8,7 +8,7 @@
   "dependencies": {
     "archiver": "^2.1.1",
     "body-parser": "^1.18.2",
-    "bootstrap": "^4.0.0",
+    "bootstrap": "^4.3.1",
     "connect-busboy": "^0.0.2",
     "connect-flash": "^0.1.1",
     "express": "^4.16.2",

yarn.lock

@@ -107,9 +107,9 @@ body-parser@1.18.2, body-parser@^1.18.2:
     raw-body "2.3.2"
     type-is "~1.6.15"
 
-bootstrap@^4.0.0:
-  version "4.0.0"
-  resolved "https://registry.yarnpkg.com/bootstrap/-/bootstrap-4.0.0.tgz#ceb03842c145fcc1b9b4e15da2a05656ba68469a"
+bootstrap@^4.3.1:
+  version "4.3.1"
+  resolved "https://registry.yarnpkg.com/bootstrap/-/bootstrap-4.3.1.tgz#280ca8f610504d99d7b6b4bfc4b68cec601704ac"
 
 brace-expansion@^1.1.7:
   version "1.1.11"