feat(sterni/external): add likely-music

This is an old project of mine, I have still deployed because a friend
was interested in using it (I think they never did though). The
repository can't be subtree-ed at the moment since it is AGPL and also
contains some personal information I would prefer not to check into such
a long-lived repository. Relicensing and subtree-ing it using a
semi-elaborate josh filter would be possible in the future, but I'm not
sure if it is worth it yet. This is probably good enough for now, the
project also very rarely breaks on channel updates.

Change-Id: I8948961406f345731d5e075e47c15901c16ca27f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7290
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI

users/sterni/external/likely-music.nix

@@ -0,0 +1,11 @@
+{ depot, pkgs, ... }:
+
+import depot.users.sterni.external.sources.likely-music
+  {
+    inherit pkgs;
+    inherit (depot.third_party) napalm;
+  } // {
+  meta.ci.targets = [
+    "likely-music"
+  ];
+}

users/sterni/external/sources.json

@@ -10,5 +10,17 @@
         "type": "tarball",
         "url": "https://github.com/openlab-aux/flipdot-gschichtler/archive/93683a7fff04e167963b70a8906f982567646501.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "likely-music": {
+        "branch": "master",
+        "description": "experimental application for probabilistic music composition",
+        "homepage": "",
+        "owner": "sternenseemann",
+        "repo": "likely-music",
+        "rev": "769e9ae049646d436c27ed21650461cdb7f9815d",
+        "sha256": "0rs3ycn0rp621zisfwlsw01l4y0h5841xnc1di0mvizxsmxhl2l9",
+        "type": "tarball",
+        "url": "https://github.com/sternenseemann/likely-music/archive/769e9ae049646d436c27ed21650461cdb7f9815d.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     }
 }