fix: add issues write permission to Docker Security Scan workflow

[kusold]

Problem

The Docker Security Scan workflow was failing with a 403 error when trying to create/update GitHub issues for detected vulnerabilities.

Error: Resource not accessible by integration

Solution

Added issues: write permission to the workflow permissions block. This allows the workflow to create and update issues to notify about security vulnerabilities.

Change

permissions:
  contents: read
+ issues: write
  packages: write
  security-events: write
  id-token: write

Testing

After this PR merges, the workflow should be able to successfully create/update issues when vulnerabilities are detected.