fix nil pointer dereference

[avarei]

Description of your changes

in a composition for a namespaced XR I tried use ExtraResources with namespace and got a nil pointer dereference panic.

apiVersion: meta.gotemplating.fn.crossplane.io/v1alpha1
kind: ExtraResources
requirements:
  token:
    apiVersion: v1
    kind: Secret
    matchName: example
    namespace: default

so i switched it around.

Fixes #

I have:

• Read and followed Crossplane's contribution process.
• Added or updated unit tests for my change.

[bobh66]

Thanks @avarei - that LGTM. Is there an existing unit test that should have caught this problem? If not does it make sense to add one?

[avarei]

Thanks for the quick review @bobh66.
I added a small test case for namespaced required resource.