Restrict sqlite3 for the extension generator

The task itself is fine, as it inherits from
Rails' app generator, which has the sqlite3 restriction:
https://github.com/rails/rails/blob/main/railties/lib/rails/generators/database.rb#L19.

Author: mamhoff

.circleci/config.yml

@@ -224,7 +224,8 @@ commands:
             cd /tmp/dummy_extension
             bundle init
             bundle add rails -v "< 7.1" --skip-install
-            bundle add sqlite3 <<parameters.extra_gems>> --skip-install
+            bundle add sqlite3 -v "~> 1.3" --skip-install
+            if [ -n "<<parameters.extra_gems>>"]; then bundle add <<parameters.extra_gems>> --skip-install; fi
             bundle add solidus --path "$(ruby -e"puts File.expand_path ENV['CIRCLE_WORKING_DIRECTORY']")"
             export LIB_NAME=set # dummy requireable file
             bundle exec rake -rrails -rspree/testing_support/extension_rake -e'Rake::Task["extension:test_app"].invoke'