fix: shuup/front/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-POSTCSS-1090595

shuup/front/package.json

@@ -16,7 +16,7 @@
     "@babel/cli": "7.12.7",
     "@babel/core": "7.12.7",
     "@babel/preset-env": "7.12.7",
-    "autoprefixer": "^9.6.1",
+    "autoprefixer": "^10.0.0",
     "babel-polyfill": "^6.26.0",
     "babel-preset-env": "^1.7.0",
     "bootstrap": "^3.4.1",
@@ -29,7 +29,7 @@
     "open-sans-all": "0.1.3",
     "owl.carousel": "^2.3.4",
     "parcel-bundler": "^1.12.4",
-    "postcss-modules": "^1.1.0",
+    "postcss-modules": "^4.0.0",
     "sass": "^1.15.1",
     "select2": "^4.0.12",
     "shuup-static-build-tools": "^1.0.3",