v0.13.50: Release 0.13.50 (#4292)

DAML Compiler

• damlc test now initializes the packagedb automatically which means
  that it will work on projects that declare custom dependencies in
  daml.yaml without having to call damlc init first.
• Choices marked explicitly as preconsuming are now equivalent to a
  nonconsuming choice that calls archive self at the beginning.

DAML Integration Kit

• The simplified kvutils API now uses com.digitalasset.resources to
  manage acquiring and releasing resources instead of Closeable.

DAML Standard Library

• Add CanAbort instance for Either Text.

DAML Studio

• Support all build-options supported by daml build.

Sandbox

• On initialization error, report the error correctly and exit with a
  status code of 1. Previously, the program would hang indefinitely.
  (This regression was introduced in v0.13.41.)
• Upgrade the Flyway database migrations library from v5 to v6.

DAML Triggers - Experimental

• DAML triggers can now be tested in scenarios. Specifically, a
  trigger's rule can be executed in a scenario and assertions
  performed on the emitted commands.