build(deps-dev): [security] bump bootstrap from 3.3.7 to 4.1.2

Bumps [bootstrap](https://github.com/twbs/bootstrap) from 3.3.7 to 4.1.2. **This update includes security fixes.**
- [Release notes](https://github.com/twbs/bootstrap/releases)
- [Commits](https://github.com/twbs/bootstrap/compare/v3.3.7...v4.1.2)

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

dapps/templates/demo/package.json

@@ -33,7 +33,7 @@
     "url": "https://github.com/embark-framework/embark.git"
   },
   "devDependencies": {
-    "bootstrap": "3.3.7",
+    "bootstrap": "4.1.2",
     "embark": "^4.1.0",
     "embark-reset": "^4.1.0",
     "npm-run-all": "4.1.5",

dapps/tests/app/package.json

@@ -2,7 +2,7 @@
   "description": "Test DApp for integration testing purposes",
   "devDependencies": {
     "@babel/code-frame": "7.0.0",
-    "bootstrap": "3.4.0",
+    "bootstrap": "4.1.2",
     "embark": "^4.1.0",
     "embark-dapp-test-service": "^4.0.0",
     "embark-i18n": "^4.1.0",

yarn.lock

@@ -4919,15 +4919,10 @@ boolbase@^1.0.0, boolbase@~1.0.0:
   resolved "https://registry.yarnpkg.com/boolbase/-/boolbase-1.0.0.tgz#68dff5fbe60c51eb37725ea9e3ed310dcc1e776e"
   integrity sha1-aN/1++YMUes3cl6p4+0xDcwed24=
 
-bootstrap@3.3.7:
-  version "3.3.7"
-  resolved "https://registry.yarnpkg.com/bootstrap/-/bootstrap-3.3.7.tgz#5a389394549f23330875a3b150656574f8a9eb71"
-  integrity sha1-WjiTlFSfIzMIdaOxUGVldPip63E=
-
-bootstrap@3.4.0:
-  version "3.4.0"
-  resolved "https://registry.yarnpkg.com/bootstrap/-/bootstrap-3.4.0.tgz#f8d77540dd3062283d2ae7687e21c1e691961640"
-  integrity sha512-F1yTDO9OHKH0xjl03DsOe8Nu1OWBIeAugGMhy3UTIYDdbbIPesQIhCEbj+HEr6wqlwweGAlP8F3OBC6kEuhFuw==
+bootstrap@4.1.2:
+  version "4.1.2"
+  resolved "https://registry.yarnpkg.com/bootstrap/-/bootstrap-4.1.2.tgz#aee2a93472e61c471fc79fb475531dcbc87de326"
+  integrity sha512-3bP609EdMc/8EwgGp8KgpN8HwnR4V4lZ9CTi5pImMrXNxpkw7dK1B05aMwQWpG1ZWmTLlBSN/uzkuz5GsmQNFA==
 
 bootstrap@^4.1.3:
   version "4.2.1"