Added HSL and HSV colors

HSL_test.go

@@ -0,0 +1,26 @@
+package color_test
+
+import (
+	"fmt"
+	"testing"
+
+	"git.urbach.dev/go/color"
+)
+
+func TestHSLSpectrum(t *testing.T) {
+	color.Terminal = true
+	color.TrueColor = true
+
+	for lightness := range 21 {
+		for hue := range 80 {
+			h := color.Value(hue) * 4.4
+			s := color.Value(1.0)
+			l := color.Value(lightness) * 0.05
+
+			c := color.HSL(h, s, l)
+			c.Print("█")
+		}
+
+		fmt.Println()
+	}
+}