Pin goimports to v0.30.0

What does this MR do?

The latest goimports is v0.31.0, which causes daily build to fail. This MR pins goimports to v0.30.0.

What are the relevant issue numbers?

Upgrade secure analyzers to go 1.24.2 (gitlab-org/gitlab#523514) • Unassigned • Backlog

Does this MR meet the acceptance criteria?

• Tests added for this feature/bug
  • After pinning to v0.30.0, the goimports job is successful https://gitlab.com/gitlab-org/security-products/analyzers/sobelow/-/jobs/9326499311
  • Before the pinning, the goimports job fails https://gitlab.com/gitlab-org/security-products/analyzers/sobelow/-/jobs/9325395248