Update docker.io/cibuilds/hugo Docker tag to v0.88

.gitlab-ci.yml

@@ -22,7 +22,7 @@ spellcheck:
     - mdspell -r -n -a --en-gb "content/posts/*.md" "content/posts/*.markdown"
 
 build:
-  image: docker.io/cibuilds/hugo:0.83
+  image: docker.io/cibuilds/hugo:0.88
   stage: build
   variables:
     HUGO_ENV: production