update lockfile

Author: philschatz

yarn.lock

@@ -1470,9 +1470,9 @@ slice-ansi@1.0.0:
   dependencies:
     is-fullwidth-code-point "^2.0.0"
 
-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@0.7.3:
+  version "0.7.3"
+  resolved "https://registry.yarnpkg.com/source-map/-/source-map-0.7.3.tgz#5302f8169031735226544092e64981f751750383"
 
 source-map@^0.5.3:
   version "0.5.7"