feat: support Node 18 and future LTS releases

BREAKING CHANGE: no longer supports Node 12

Various libraries are starting to drop support for Node 12.
While this only affects the dev dependencies of this project
it's only a matter of time before something critical drops
support. So to keep maintenance easy, we're dropping
v12 now as it is past EOL already and moving to 14, 16,
and 18 LTS versions.

Recommended action: upgrade your project from Node 12
to a later LTS release (14, 16, 18)

README.md

@@ -103,7 +103,6 @@ URL to the content API for Scene7. Default when not set is `http://s7d1.scene7.c
 URL to the content API for Scene7 where losed caption and chapter navigation assets are located. Default when not set is `http://s7d1.scene7.com/is/content/`
 
 
-
 ## License
 
 MIT. Copyright (c) Anthony McLin <npm@anthonymclin.com>