Stop regenerating gh-pages index.md in release script

Hugo on `main` now owns the Pages index, so the release script no
longer needs to write a Jekyll front-matter wrapper around README.md
on the gh-pages branch. The Javadoc-publishing block that creates
`doc/$tag/` and updates the `doc/latest` symlink is unchanged — that
versioned tree continues to live on gh-pages and is preserved by the
new workflow's `keep_files: true`.

For STF-448.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: oschwald

dev-bin/release.sh

@@ -118,17 +118,6 @@ if [ "$should_continue" != "y" ]; then
     exit 1
 fi
 
-page=.gh-pages/index.md
-cat <<EOF >$page
----
-layout: default
-title: MaxMind DB Java API
-language: java
-version: $tag
----
-
-EOF
-
 mvn versions:set -DnewVersion="$version"
 
 perl -pi -e "s/(?<=<version>)[^<]*/$version/" README.md
@@ -137,8 +126,6 @@ perl -pi -e "s/(?<=com\.maxmind\.db\:maxmind-db\:)\d+\.\d+\.\d+([\w\-]+)?/$versi
 # Update japicmp.baselineVersion for API compatibility checking
 perl -pi -e "s/(<japicmp\.baselineVersion>)[^<]*(<\/japicmp\.baselineVersion>)/\${1}$version\${2}/" pom.xml
 
-cat README.md >>$page
-
 git diff
 
 read -r -n 1 -p "Commit changes? " should_commit