Libvips 8.7.0 and Sharp 0.21.3

The new release updates Libvips library code and then tests it against the sharp node library:

• Archive libvips-8.7.0-lambda.tar.gz contains the Libvips library (without Php modules).
• Archive sharp-0.21.3-libvips-8.7.0-lambda.tar.gz contains the sharp node library compiled and tested against the Libvips library.

The docker environment used is stechstudio/aws-lambda-build:1.2.3 that can be created with version 1.2.3 of project aws-lambda-build.