Add a error-detection config for older versions of Hugo

[chalin]

• Closes Warn about Hugo versions prior to 0.110.0 #228
• E.g., when using Hugo 0.109:

  $ npx hugo
  WARN 2023/06/26 16:59:04 Module "project" is not compatible with this Hugo version; run "hugo mod graph" for more information.
  Start building sites … 
  hugo v0.109.0-47b12b83e636224e5e601813ff3e6790c191e371+extended darwin/amd64 BuildDate=2022-12-23T10:38:11Z VendorInfo=gohugoio
  Error: Error building site: "/Users/chalin/git/lf/docsy/docsy-example/content/en/_index.md:5:1": failed to extract shortcode: template for shortcode "blocks/cover" not found
  Total in 21 ms

• Adding this config file does not (seem to) affect builds using Hugo 0.110.0 and later (as we can see from the build of this PR).

/cc @geriom

[deining]

Great idea!
LGTM!