Consider using environment_url instead of log_url for target environment

Based on what I'm seeing here and the behavior I'm seeing in Jira, the integration between jira is using the deployment status log_url instead of the environment_url. Given that I believe the link is to supposed to go to the deployment url, can we change this to point to the `environment_url` property in the github deployment status instead of the `log_url`?

https://github.com/atlassian/github-for-jira/blob/e60fdc9153081f32bd0574d680a12522e1021f25/src/sync/deployment.ts#L67

Start in src/sync/deployment.ts at line 67 and inspect how the GitHub deployment status URL is selected for Jira. Confirm the target link should use environment_url rather than log_url, then verify that the Jira deployment link points to the environment URL.

Written by the indexing model from the issue text.