[Epic] Test/Enable Node.js 12 support for connectors

[dhmlau]

Through PR loopbackio/loopback-datasource-juggler#1728 and loopbackio/loopback-datasource-juggler#1729, loopback-datasource-juggler now supports Node.js 12. The next step is to test and add support for Node.js 12.x for the connectors.

Acceptance Criteria

For the following connectors, test locally on Node.js 12 and see if all tests passed.

• If yes, add Node.js 12 to CI
• If not, try to fix it for simple fixes. If you don't think you can fix it in a day, open a new issue to keep track of it.

Here is the list of connectors:

SQL connectors: #3110

• loopback-connector
• loopback-connector-mysql
• loopback-connector-postgresql
• loopback-connector-mssql
• loopback-connector-oracle
• loopback-connector-db2 (doesn't work with node 12 yet)

noSQL connectors: #3111

• loopback-connector-mongodb
• loopback-connector-couchdb2
• loopback-connector-cloudant
• loopback-connector-cassandra

service connectors: #3112

• loopback-connector-remote
• loopback-connector-rest
• loopback-connector-soap
• loopback-connector-swagger deprecated
• loopback-connector-jsonrpc
• loopback-connector-openapi

currently with CI issues:

• loopback-connector-kv-redis
• loopback-connector-grpc
• loopback-connector-mqlight
• loopback-connector-dashdb (doesn't work with node 12 yet)
• loopback-connector-kv-extreme-scale

not sure if we need to enable Node.js 12

• loopback-connector-db2iseries (we don't have an instance to test??)
• loopback-connector-informix (we don't have an instance to test??)
• loopback-connector-db2z (we don't have an instance to test??)
• loopback-connector-zosconnectee (??)

I'm taking the list from https://github.com/strongloop?utf8=%E2%9C%93&q=loopback-connector&type=&language=

[dhmlau]

We've enabled and tested the most commonly used connectors with Node.js 12. For the rest, we'll enable it later. Moving to Q4.

[dhmlau]

We have finished the requirement for Q4, i.e. enable and test Node.js 12 for:

• loopback-connector-kv-redis
• loopback-connector-grpc

Moving the 2019Q4 label.

[dhmlau]

Consider it done. The rest are not very active repos.