chore: bump ruby/setup-ruby from 1.215.0 to 1.216.0

Author: kaylareopelle

.github/actions/test_gem/action.yml

@@ -84,7 +84,7 @@ runs:
     # ...but not for appraisals, sadly.
     - name: Install Ruby ${{ inputs.ruby }} with dependencies
       if: "${{ steps.setup.outputs.appraisals == 'false' }}"
-      uses: ruby/setup-ruby@v1.215.0
+      uses: ruby/setup-ruby@v1.216.0
       with:
         ruby-version: "${{ inputs.ruby }}"
         working-directory: "${{ steps.setup.outputs.gem_dir }}"
@@ -95,7 +95,7 @@ runs:
     # If we're using appraisals, do it all manually.
     - name: Install Ruby ${{ inputs.ruby }} without dependencies
       if: "${{ steps.setup.outputs.appraisals == 'true' }}"
-      uses: ruby/setup-ruby@v1.215.0
+      uses: ruby/setup-ruby@v1.216.0
       with:
         ruby-version: "${{ inputs.ruby }}"
         bundler:  "latest"