LICENSE: remove trailing newline (#61)

Discovered while vendoring this repo, and having a check for trailing
whitespace. (e.g. `git show --check 45e9319`)

Signed-off-by: Vincent Batts <vbatts@hashbangbash.com>

LICENSE

@@ -21,4 +21,3 @@ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-