[Feature Request]: add documentation on maintaining transform update compatiblity when performing changes

[chamikaramj]

What would you like to happen?

Beam supports upgrading specific transforms to new Beam versions using the Transform Service: https://beam.apache.org/documentation/programming-guide/#transform-service-usage-upgrade

We should add documentation on maintaining update compatibility when performing transform changes (for example, when adding new fields to the builders).

Issue Priority

Priority: 3 (nice-to-have improvement)

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[liferoad]

@xianhualiu could you take this issue?