remove trivyignore file

[ashnamehrotra]

What steps did you take and what happened:
[A clear and concise description of what the bug is.]
Remove trivyignore file since we want to be able to detect this vulnerability later.
(Added in PR #877)

What did you expect to happen:

Anything else you would like to add:
[Miscellaneous information that will assist in solving the issue.]

Environment:

• Eraser version:
• Kubernetes version: (use kubectl version):