[Bug]: Need to update outdated node before website tools break.

[robertwb]

What happened?

Our website building tools, as documented at https://github.com/apache/beam/blob/master/website/README.md , apparently rely on too-old Node 14. Building gives errors like

#8 0.367                               DEPRECATION WARNING                            
#8 0.367 
#8 0.367   Node.js 14.x is no longer actively supported!

and

#8 20.37                            SCRIPT DEPRECATION WARNING                    
#8 20.37 
#8 20.37   
#8 20.37   This script, located at https://deb.nodesource.com/setup_X, used to
#8 20.37   install Node.js is deprecated now and will eventually be made inactive.

Issue Priority

Priority: 1 (data loss / total loss of function)

Issue Components

• Component: Python SDK
• Component: Java SDK
• Component: Go SDK
• Component: Typescript SDK
• Component: IO connector
• Component: Beam YAML
• Component: Beam examples
• Component: Beam playground
• Component: Beam katas
• Component: Website
• Component: Spark Runner
• Component: Flink Runner
• Component: Samza Runner
• Component: Twister2 Runner
• Component: Hazelcast Jet Runner
• Component: Google Cloud Dataflow Runner