ci: bump Hugo from 0.146.3 to 0.166.0 (#12281)

The hugo-theme-relearn submodule was bumped to 9.1.x in #12096,
which requires Hugo >= 0.165.0. The pinned 0.146.3 broke the docs
site build with a template error in alias.html that could not
evaluate the Locale field on langs.Language.

Bump HUGO_VERSION to 0.166.0 (latest stable) to satisfy the
theme minimum and resolve the alias.html template error.

Assisted-by: nib:claude-sonnet-4.5 [bash] [read] [edit]

Co-authored-by: Ettore Di Giacinto <mudler@localai.io>

.github/workflows/gh-pages.yml

@@ -40,7 +40,7 @@ jobs:
     # fetch their own toolchains, and no step uses sudo, apt, make or unzip.
     runs-on: ${{ github.repository == 'mudler/LocalAI' && 'arc-runner-set' || 'ubuntu-latest' }}
     env:
-      HUGO_VERSION: "0.146.3"
+      HUGO_VERSION: "0.166.0"
     steps:
       - name: Checkout
         uses: actions/checkout@v7