Cloud: Issue.DownloadAttachment is using deprecated API

[markuszm]

What happened?

Jira Cloud deprecated multiple endpoints regarding attachment and thumbnail downloads, see https://community.developer.atlassian.com/t/deprecation-of-obsolete-jira-cloud-download-attachment-and-thumbnail-urls.
This affects the Issue.DownloadAttachment method as it uses the deprecated method.
Since 4. February, the methods are removed from the cloud instance, as such the DownloadAttachment function does not work anymore.
Affected code line is: https://github.com/andygrunwald/go-jira/blob/main/cloud/issue.go#L656.

What did you expect to happen?

DownloadAttachment method works properly.

How can we reproduce it (as minimally and precisely as possible)?

Create an attachment and then download it using the plain jira.Issue methods.

Anything else we need to know?

Not sure if other methods are also affected related to thumbnails.

Your Environment

Include as many relevant details about the environment you experienced the problem in

• go-jira version (git tag or sha):v2.0.0-20240116150243-50d59fe116d6
• Go version (go version):1.22
• Jira type (cloud or on-premise):cloud
• Jira version / Api version:1001.0.0-SNAPSHOT