Update postcss version

Author: taphill

package.json

@@ -10,7 +10,7 @@
     "@tailwindcss/typography": "^0.4.0",
     "autoprefixer": "^9",
     "jquery": "^3.5.1",
-    "postcss": "^7",
+    "postcss": "^8",
     "tailwindcss": "npm:@tailwindcss/postcss7-compat",
     "turbolinks": "^5.2.0",
     "webpack-dev-server": "3.11.2"

yarn.lock

@@ -5736,7 +5736,7 @@ postcss@^7, postcss@^7.0.0, postcss@^7.0.1, postcss@^7.0.14, postcss@^7.0.17, po
     picocolors "^0.2.1"
     source-map "^0.6.1"
 
-postcss@^8.3.5:
+postcss@^8, postcss@^8.3.5:
   version "8.4.5"
   resolved "https://registry.yarnpkg.com/postcss/-/postcss-8.4.5.tgz#bae665764dfd4c6fcc24dc0fdf7e7aa00cc77f95"
   integrity sha512-jBDboWM8qpaqwkMwItqTQTiFikhs/67OYVvblFFTM7MrZjt6yMKd6r2kgXizEbTTljacm4NldIlZnhbjr84QYg==