Pin PurgeCSS to ^3 for compat build

adamwathan · adamwathan · commit 204ad22ec8bb · 2021-05-31T08:57:45.000-04:00
diff --git a/package.postcss7.json b/package.postcss7.json
@@ -1,5 +1,6 @@
 {
   "dependencies": {
+    "@fullhuman/postcss-purgecss": "^3.1.3",
     "autoprefixer": "^9",
     "postcss": "^7",
     "postcss-functions": "^3",
