Lock json-schema-5.1.0

Author: hsbt

common.mk

@@ -1605,7 +1605,7 @@ no-install-for-test-bundled-gems: no-update-default-gemspecs
 yes-install-for-test-bundled-gems: yes-update-default-gemspecs
 	$(XRUBY) -C "$(srcdir)" -r./tool/lib/gem_env.rb bin/gem \
 		install --no-document --conservative \
-		"hoe" "json-schema" "test-unit-rr" "simplecov" "simplecov-html" "simplecov-json" "rspec" "zeitwerk" \
+		"hoe" "json-schema:5.1.0" "test-unit-rr" "simplecov" "simplecov-html" "simplecov-json" "rspec" "zeitwerk" \
 		"sinatra" "rack" "tilt" "mustermann" "base64" "compact_index" "rack-test"
 
 test-bundled-gems-fetch: yes-test-bundled-gems-fetch