make: integration-test: KUBEBUILDER_ASSETS needs to be absolute
make: integration-test: KUBEBUILDER_ASSETS needs to be absolute

It seems like Ginkgo isn't running from the root of the repository, that's why
it can't find binaries, e.g., bin/tools/etcd.

Signed-off-by: Maël Valais <d58a90d9f168821bded9222e523244d2fab951f8@vls.dev>

cert-manager/cert-manager,jetstack/cert-manager,cert-manager/cert-manager,jetstack/cert-manager,cert-manager/cert-manager,jetstack/cert-manager