Update generate-changelog.yml

Trying to install the gem locally.

Author: sirkitree

.github/workflows/generate-changelog.yml

@@ -10,7 +10,7 @@ jobs:
       - uses: actions/checkout@v4
       - name: Generate Changelog
         run: |
-          gem install github_changelog_generator
+          gem install --user-install github_changelog_generator
           github_changelog_generator \
             -u ${{ github.repository_owner }} \
             -p ${{ github.event.repository.name }} \