connect: use the public /v1/tasks/{id} endpoint

[aronatkins]

Intent

The v0 task is still returned by the v0 deploy endpoint.

• poll-wait is an integer, not a float, and is used to configure the long-poll task requests against the Connect server.

• task_get() calls /v1/tasks/{id}. It takes first and wait arguments, indicating the starting point for requested output and the duration for long-poll requests.

• wait_for_task() does no sleeping, but asks task_get() to perform a long-poll with its wait argument.

• output_task_log() sends every output line to the log callback. It previously used data abut the last-line to determine when to send lines, but that is unnecessary, as wait_for_task() requests only new lines from task_get().

• RSConnectExecutor.delete_runtime_cache() returns its delete result and task for easier testing. It no longer stores state on the object.

fixes #608

Type of Change

• [ ] Bug Fix
• [ ] New Feature
• [ ] Breaking Change

Approach

Automated Tests

Directions for Reviewers

• deploy any content and confirm that the output is shown.
• delete runtime caches and confirm that the output is shown.
• queue and run any content rebuild and confirm that the output is shown.

Checklist

• [x] I have updated CHANGELOG.md to cover notable changes.
• [x] I have updated all related GitHub issues to reflect their current state.