Test against Node.js v21

[achrinza]

#TODO: Include description and repos to update.

Repositories to update

• loopback-next
• loopback-connector
• loopback-connector-cassandra
• loopback-connector-cloudant
• loopback-connector-couchdb2
• loopback-connector-dashdb
• loopback-connector-db2
• loopback-connector-elastic-search
• loopback-connector-grpc
• loopback-connector-ibmi
• loopback-connector-kv-redis
• loopback-connector-mongodb
• loopback-connector-mssql
• loopback-connector-mysql
• loopback-connector-openapi
• loopback-connector-oracle
• loopback-connector-postgresql
• loopback-connector-redis
• loopback-connector-rest
• loopback-connector-soap
• loopback-connector-sqlite3
• loopback-datasource-juggler
• loopback-ibmdb
• loopback4-example-shopping
• strong-error-handler
• strong-soap

Other references

see: nodejs/node#49870
see: nodejs/Release#938