Bump bootstrap-sass from 3.3.7 to 3.4.1 in /app/assets

Bumps [bootstrap-sass](https://github.com/twbs/bootstrap-sass) from 3.3.7 to 3.4.1.
- [Release notes](https://github.com/twbs/bootstrap-sass/releases)
- [Changelog](https://github.com/twbs/bootstrap-sass/blob/master/CHANGELOG.md)
- [Commits](twbs/bootstrap-sass@v3.3.7...v3.4.1)

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

Signed-off-by: dependabot[bot] <[email protected]>

app/assets/package.json

@@ -19,7 +19,7 @@
     "@fontsource/source-code-pro": "^4.5.1",
     "cross-env": "^5.2.1",
     "jquery": "2.2.4",
-    "bootstrap-sass": "3.3.6",
+    "bootstrap-sass": "3.4.1",
     "bootstrap-filestyle": "1.2.1",
     "fuse.js": "^3.2.0",
     "floatthead": "^2.1.2",

app/assets/yarn.lock

@@ -1710,10 +1710,10 @@ [email protected]:
   resolved "https://registry.yarnpkg.com/bootstrap-filestyle/-/bootstrap-filestyle-1.2.1.tgz#4164271d5b101ec867565eebbdab25d210a581a0"
   integrity sha1-QWQnHVsQHshnVl7rvasl0hClgaA=
 
-bootstrap-sass@3.3.6:
-  version "3.3.6"
-  resolved "https://registry.yarnpkg.com/bootstrap-sass/-/bootstrap-sass-3.3.6.tgz#363b0d300e868d3e70134c1a742bb17288444fd1"
-  integrity sha1-NjsNMA6GjT5wE0wadCuxcohET9E=
+bootstrap-sass@3.4.1:
+  version "3.4.1"
+  resolved "https://registry.yarnpkg.com/bootstrap-sass/-/bootstrap-sass-3.4.1.tgz#6843c73b1c258a0ac5cb2cc6f6f5285b664a8e9a"
+  integrity sha512-p5rxsK/IyEDQm2CwiHxxUi0MZZtvVFbhWmyMOt4lLkA4bujDA1TGoKT0i1FKIWiugAdP+kK8T5KMDFIKQCLYIA==
 
 bootstrap-select@^1.13.5:
   version "1.13.18"