Set uid & gid when copying to find-sec-bugs-gradle

What does this MR do?

It sets the uid & gid of the files copied to the find-sec-bugs-gradle container.

Why was this MR needed?

That's because the uid & gid of the project directory must match the gradle user & group otherwise the gradle user running the gradle command can't create the build directory and others.

It seems like there's no generic way to set the uid & gid to match the default user of the target container, so these have been hardcoded to 1000 in the case of the find-sec-bugs-gradle container.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/security-products/analyzers/find-sec-bugs-gradle/issues/2