Pin ava@1

Author: SamVerschueren

package.json

@@ -50,7 +50,7 @@
 	"devDependencies": {
 		"@types/node": "^11.10.4",
 		"@types/update-notifier": "^2.2.0",
-		"ava": "*",
+		"ava": "^1.4.1",
 		"cpy-cli": "^2.0.0",
 		"del-cli": "^1.1.0",
 		"tslint": "^5.11.0",