Merge pull request #535 from textpattern/dependabot/npm_and_yarn/autoprefixer-10.4.13

Bump autoprefixer from 10.4.2 to 10.4.13

Author: philwareham

package.json

@@ -12,7 +12,7 @@
   "devDependencies": {
     "@lodder/grunt-postcss": "3.1.1",
     "@squoosh/cli": "0.7.2",
-    "autoprefixer": "10.4.2",
+    "autoprefixer": "10.4.13",
     "cssnano": "5.1.14",
     "grunt": "1.5.3",
     "grunt-cli": "1.4.3",