update all downstream dependencies

no specific features I'm looking to add, just keeping thing up to date.
Unit tests and my manual testing seems like everything is still working
as expected.

vendor/github.com/disintegration/imaging/histogram.go

@@ -0,0 +1,43 @@
+package imaging
+
+import (
+	"image"
+)
+
+// Histogram returns a normalized histogram of an image.
+//
+// Resulting histogram is represented as an array of 256 floats, where
+// histogram[i] is a probability of a pixel being of a particular luminance i.
+func Histogram(img image.Image) [256]float64 {
+	src := toNRGBA(img)
+	width := src.Bounds().Max.X
+	height := src.Bounds().Max.Y
+
+	var histogram [256]float64
+	var total float64
+
+	if width == 0 || height == 0 {
+		return histogram
+	}
+
+	for y := 0; y < height; y++ {
+		for x := 0; x < width; x++ {
+			i := y*src.Stride + x*4
+
+			r := src.Pix[i+0]
+			g := src.Pix[i+1]
+			b := src.Pix[i+2]
+
+			var y float32 = 0.299*float32(r) + 0.587*float32(g) + 0.114*float32(b)
+
+			histogram[int(y+0.5)]++
+			total++
+		}
+	}
+
+	for i := 0; i < 256; i++ {
+		histogram[i] = histogram[i] / total
+	}
+
+	return histogram
+}