servlet-api dependency should not be transitive

[kelseyfrancis]

No description provided.

[chris-martin]

I realize that the Servlet API is the canonical example of a provided dependency ...

[...] when building a web application for the Java Enterprise Edition, you would set the dependency on the Servlet API and related Java EE APIs to scope provided because the web container provides those classes.

https://maven.apache.org/guides/introduction/introduction-to-dependency-mechanism.html

... but in this case, for-webapps could conceivably be used in a web application that doesn't involve the Servlet API. So I think it should actually be an optional dependency.

Now I'm trying to figure out: Is there actually any difference between <scope>provided</scope> and <optional>true</optional>? In both cases, the dependency is not transitive and is available at compile time.