Unfortunately AWS removes older Greengrass downloads as soon as they release the new version, and they do not provide early warning to partners regarding new releases.
We are actively engaged with AWS trying to find a solution for this.
Digi is just about to release a new Digi Embedded Yocto release, dey-2.2-r3, but unfortunately this updates Greengrass to the 1.1.0 version as the 1.3.0 release happened just a couple of weeks ago. The next Greengrass update will have to wait until the next release in 3/4 months.
I suggest you contact Digi support by email and we will send you a patch for the 1.3.0 update as soon as it's ready, even before it's officially released with DEY.
Until then, please develop using the 1.1.0 version.