Upgrade to libvips v8.9.0-rc4, drop support for Node.js 8

lib/channel.js

@@ -32,6 +32,8 @@ function removeAlpha () {
 /**
  * Ensure alpha channel, if missing. The added alpha channel will be fully opaque. This is a no-op if the image already has an alpha channel.
  *
+ * @since 0.21.2
+ *
  * @example
  * sharp('rgb.jpg')
  *   .ensureAlpha()

lib/composite.js

@@ -53,6 +53,8 @@ const blend = {
  * https://libvips.github.io/libvips/API/current/libvips-conversion.html#VipsBlendMode
  * and https://www.cairographics.org/operators/
  *
+ * @since 0.22.0
+ *
  * @example
  * sharp('input.png')
  *   .rotate(180)

lib/operation.js

@@ -379,6 +379,8 @@ function linear (a, b) {
 /**
  * Recomb the image with the specified matrix.
  *
+ * @since 0.21.1
+ *
  * @example
  * sharp(input)
  *   .recomb([
@@ -416,6 +418,8 @@ function recomb (inputMatrix) {
 /**
  * Transforms the image using brightness, saturation and hue rotation.
  *
+ * @since 0.22.1
+ *
  * @example
  * sharp(input)
  *   .modulate({

lib/output.js

@@ -444,6 +444,8 @@ function tiff (options) {
  *
  * Most versions of libheif support only the patent-encumbered HEVC compression format.
  *
+ * @since 0.23.0
+ *
  * @param {Object} [options] - output options
  * @param {Number} [options.quality=80] - quality, integer 1-100
  * @param {Boolean} [options.compression='hevc'] - compression format: hevc, avc, jpeg, av1