[lib] limit apache-beam version <2.25.0

[DanSimon]

2.25.0 has transitive dependencies that cause conflicts:

google-cloud-build 2.0.0 has requirement google-api-core[grpc]<2.0.0dev,>=1.22.0, but you have google-api-core 1.20.1.
google-cloud-bigquery 1.28.0 has requirement google-api-core<2.0dev,>=1.21.0, but you have google-api-core 1.20.1.

Also, 2.25.0 has changed BigQuerySource from a class to a function, and since we have classes that inherit from it, Klio is currently incompatible with it.

Checklist for PR author(s)

• Format the pull request title like [cli] Fixes bugs in 'klio job fake-cmd'.
• Changes are covered by unit tests (no major decrease in code coverage %) and/or integration tests.
• Document any relevant additions/changes in the appropriate spot in docs/src.

[fallonchen]