Bump underscore from 1.13.3 to 1.13.4

Bumps [underscore](https://github.com/jashkenas/underscore) from 1.13.3 to 1.13.4.
- [Release notes](https://github.com/jashkenas/underscore/releases)
- [Commits](https://github.com/jashkenas/underscore/compare/1.13.3...1.13.4)

---
updated-dependencies:
- dependency-name: underscore
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

package.json

@@ -17,7 +17,7 @@
     "popper.js": "^1.16.1",
     "rails-erb-loader": "^5.5.2",
     "sortablejs": "^1.15.0",
-    "underscore": "^1.13.3",
+    "underscore": "^1.13.4",
     "vis": "^4.21.0",
     "webpack-merge": "^5.8.0"
   },

yarn.lock

@@ -7116,10 +7116,10 @@ unbox-primitive@^1.0.2:
     has-symbols "^1.0.3"
     which-boxed-primitive "^1.0.2"
 
-underscore@^1.13.3:
-  version "1.13.3"
-  resolved "https://registry.yarnpkg.com/underscore/-/underscore-1.13.3.tgz#54bc95f7648c5557897e5e968d0f76bc062c34ee"
-  integrity sha512-QvjkYpiD+dJJraRA8+dGAU4i7aBbb2s0S3jA45TFOvg2VgqvdCDd/3N6CqA8gluk1W91GLoXg5enMUx560QzuA==
+underscore@^1.13.4:
+  version "1.13.4"
+  resolved "https://registry.yarnpkg.com/underscore/-/underscore-1.13.4.tgz#7886b46bbdf07f768e0052f1828e1dcab40c0dee"
+  integrity sha512-BQFnUDuAQ4Yf/cYY5LNrK9NCJFKriaRbD9uR1fTeXnBeoa97W0i41qkZfGO9pSo8I5KzjAcSY2XYtdf0oKd7KQ==
 
 unicode-canonical-property-names-ecmascript@^2.0.0:
   version "2.0.0"