diff --git a/yarn.lock b/yarn.lock
index 1668c55..7db8569 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1487,8 +1487,8 @@ clap@^1.0.9:
     chalk "^1.1.3"
 
 clean-css@4.1.x:
-  version "4.1.3"
-  resolved "https://registry.yarnpkg.com/clean-css/-/clean-css-4.1.3.tgz#07cfe8980edb20d455ddc23aadcf1e04c6e509ce"
+  version "4.1.11"
+  resolved "https://registry.yarnpkg.com/clean-css/-/clean-css-4.1.11.tgz#2ecdf145aba38f54740f26cefd0ff3e03e125d6a"
   dependencies:
     source-map "0.5.x"
 
@@ -6355,10 +6355,14 @@ source-map-support@^0.4.2:
   dependencies:
     source-map "^0.5.6"
 
-source-map@0.5.6, source-map@0.5.x, source-map@^0.5.0, source-map@^0.5.3, source-map@^0.5.6, source-map@~0.5.1, source-map@~0.5.3:
+source-map@0.5.6:
   version "0.5.6"
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.5.6.tgz#75ce38f52bf0733c5a7f0c118d81334a2bb5f412"
 
+source-map@0.5.x, source-map@^0.5.0, source-map@^0.5.3, source-map@^0.5.6, source-map@~0.5.1, source-map@~0.5.3:
+  version "0.5.7"
+  resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.5.7.tgz#8a039d2d1021d22d1ea14c80d8ea468ba2ef3fcc"
+
 source-map@^0.4.4:
   version "0.4.4"
   resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.4.4.tgz#eba4f5da9c0dc999de68032d8b4f76173652036b"