ManifestsApp was updated to v1.0.4.
v1.0.4 (February 12, 2020)
“runtimeVersion” got to be able to be got and set. Now, ‘STABLE’, ‘V8’, ‘DEPRECATED_ES5’ can be used as the value of “runtimeVersion”. For example, you can enable V8 with the following script.
var r = ManifestsApp.setProjectId(projectId).setRuntimeVersion("V8"); Logger.log(r);
As one important point, when “STABLE” and “DEPRECATED_ES5” are used for the Google Apps Script project created before 2020 as the value of “runtimeVersion”, the error of
Syntax error: Illegal character.occurs. So please be careful this. This has been reported at the issuetracker.
You can check this at https://github.com/tanaikech/ManifestsApp.