feat: Add `IssueService.GetWorklogRecord`

[gabe565]

What type of PR is this?

• feature
• api-change (new function)

What this PR does / why we need it:

Jira has an API endpoint to get an issue's worklog by ID which is not currently supported by this library.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

N/A

Additional documentation e.g., usage docs, etc.:

Added tests to match API spec.