feat: add support for Hugo v0.91 breaking changes

Hugo team prevented users from building Hugo sites unless all env vars are added to an allow list.

Refer to Hugo v0.91 breaking changes: https://github.com/gohugoio/hugo/releases/tag/v0.91.0

wowchemy/config.yaml

@@ -1,5 +1,4 @@
 markup:
-  _merge: deep
   defaultMarkdownHandler: goldmark
   goldmark:
     renderer:
@@ -53,3 +52,8 @@ params:
   date_format: 'Jan 2, 2006'
   time_format: '3:04 PM'
   address_format: en-us
+security:
+  funcs:
+    getenv:
+      - ^HUGO_
+      - ^WC_