ci: test executable's version subcmd

.drone.starlark

@@ -217,6 +217,25 @@ def main(ctx):
 						"nix build .#go-xkcdreader"
 					]
 				},
+				{
+					"name": "go-xkcdreader version",
+					"image": "docker.io/nixos/nix:2.8.0-amd64",
+					"pull": "if-not-exists",
+					"depends_on": ["nix build"],
+					"volumes": [
+						{
+							"name": "nix",
+							"path": "/nix"
+						},
+						{
+							"name": "nixconf",
+							"path": "/etc/nix"
+						}
+					],
+					"commands": [
+						"./result/bin/go-xkcdreader version"
+					]
+				},
 				{
 					"name": "ldd",
 					"image": "docker.io/nixos/nix:2.8.0-amd64",