replace math/rand with the rand pkg from k8s.io/apimachinery

[tariq1890]

Fixes the gosec G404 linting issues
Removed the need to add exclude directives to the golangci-lint config file

[elezar]

As was the case with the changes for NVIDIA/k8s-device-plugin#629 I don't think these are required. These are in tests and we KNOW that the use of math/rand will not cause issues in this case.

Although the use of k8s.io/apimachinery/pkg/util/rand addresses the issues, it makes it seem as if the tests actually requrie this package -- instead of using the standard library -- and increases our external dependencies.

[elezar]

This change seems reasonable.

[tariq1890]

I'll file another PR for it

[klueska]

I don't feel strongly either way, but I do agree with the sentiment of not pulling in dependencies unless absolutely necessary. Could we move to crypto/rand instead?

[elezar]

If I recall correctly, switching to crypto/rand required a number of additional code changes and since these are _tests.go files and we're just using rand to generate a random integer:

			successAfter := rand.Intn(uniquePermutations(mc)) + 1

these changes are not required.