Docsy 0.15.0-rc

[chalin]

• Upgrades to Docsy 0.15.0 release candidate
• Upgrades Hugo to required version

No unexpected generated site diffs:

$ (cd public && git diff -bw --ignore-blank-lines -I 'target="_blank"|href="/site/"|_hu_|contribution-guidelines') | grep ^diff | grep -Ev '\.jpg|\.css'
diff --git a/fa/index.html b/fa/index.html
diff --git a/index.html b/index.html
diff --git a/index.xml b/index.xml
diff --git a/no/index.html b/no/index.html
diff --git a/site/index.html b/site/index.html