Remove unnecessary working-directory from composite action uses step and git config steps

working-directory is not supported on uses steps in composite actions.
Git credential and fetch steps operate on the repository root set up
by actions/checkout, so working-directory is unnecessary for them.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: hsbt

action.yml

@@ -53,11 +53,9 @@ runs:
     - name: Fetch tags
       run: git fetch --tags --force
       shell: bash
-      working-directory: ${{ inputs.working-directory }}
     - name: Configure trusted publishing credentials
       if: ${{ inputs.setup-trusted-publisher == 'true' }}
       uses: rubygems/configure-rubygems-credentials@bc6dd217f8a4f919d6835fcfefd470ef821f5c44 # v1.0.0
-      working-directory: ${{ inputs.working-directory }}
     - name: Run release rake task
       run: bundle exec rake release
       shell: bash