[Bug]: prerequisites incorrect link on contribution page

[derrickaw]

What happened?

beam/CONTRIBUTING.md

Line 76 in 9fd9fca

- Manually installing the [prerequisites](https://beam.apache.org/contribute/#prerequisites).

points to an old location.

.take-issue

Issue Priority

Priority: 3 (minor)

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: Infrastructure
• Component: Spark Runner
• Component: Flink Runner
• Component: Samza Runner
• Component: Twister2 Runner
• Component: Hazelcast Jet Runner
• Component: Google Cloud Dataflow Runner

[derrickaw]

.take-issue