pkg/namespace-labeler: fix whitespace
pkg/namespace-labeler: fix whitespace

There should be an empty line between license header and package
declaration otherwise the license gets interpreted as package
documentation by godoc.

Signed-off-by: Muhammad Talal Anwar <11616d23d56dbe0c789e6655395e2cd70bad7b46@outlook.com>

coreos/prometheus-operator,coreos/prometheus-operator