retire alpine workaround

See sparklemotion/sqlite3-ruby#434 (comment)

lib/generators/templates/Dockerfile.erb

@@ -87,12 +87,6 @@ ENV <%= build_env.join(" \\\n    ") %>
 <% end -%>
 # Install application gems
 COPY<% if options.link? %> --link<% end %> Gemfile Gemfile.lock <% if references_ruby_version_file? %>.ruby-version <% end %>./
-<% if options.alpine? and deploy_packages.include? 'sqlite-libs' -%>
-# Workaround sqlite/alpine issue: https://github.com/sparklemotion/sqlite3-ruby/issues/434
-RUN bundle config force_ruby_platform true && \
-    bundle config set frozen false && \
-    bundle lock --add-platform ruby
-<% end -%>
 <% if options.cache? -%>
 RUN --mount=type=cache,id=bld-gem-cache,sharing=locked,target=/srv/vendor \
 <% if private_gemserver_env_variable_name -%>