Update dart sass (#536)

Author: jarrodmillman

doc/netlify.toml

@@ -1,7 +1,7 @@
 [build.environment]
   PYTHON_VERSION = "3.8" # netlify currently only support 2.7 and 3.8
   HUGO_VERSION = "0.123.8"
-  DART_SASS_VERSION = "1.70.0"
+  DART_SASS_VERSION = "1.71.1"
   DART_SASS_URL = "https://github.com/sass/dart-sass/releases/download/"
 
 [context.production.environment]