1.3.0

Only one new feature this time, but we've fixed some annoying bugs and that's awesome! Thanks to everybody who contributed. 🥇

The highlights of the release are:

• New flag --keep-result instructs morph to create a gcroot on the local system to prevent unwanted garbage collection.
• Fix of bug #34 now allows for per-machine specific config and proper cross-platform support.

Please note: morph >=v1.3.0 will not be able to build NixOS systems prior to version 19.09.

Commits:

00d7675 aligned comment with implementation (@johanot)
e88558c Merge per-machine nixpkgs arguments on top of network-wide ones (@Shados)
3856a9c healthchecks: fix bug in http-header implementation (@johanot)
8c232a4 Describe commands: build, push and deploy (#63) (@nhey)
593352d Typo in help for --reboot option (@eskytthe)
76fa9fc gcroot: addressing review comments (@johanot)
97928f9 gcroot: fail to KeepGCRoot disabled (@krav)
1815179 Don't dereference flag before it is set, default to false (@krav)
0d4cd43 nix-build: Keep latest build result around to prevent GC (@krav)
3f098a2 SSH_SKIP_HOST_KEY_CHECK should have affect for "nix copy ssh://" as well (@johanot)