Regression: sites with `next export` should cause the plugin to no-op

[jlengstorf]

Describe the bug
Because sites using next export don't need special treatment (they generate static assets that follow the Jamstack architecture pattern), this plugin doesn't need to do anything when that option is set. However, we do want to plugin available in case folks switch from using export to using Next features that need the plugin.

To support that, we need the plugin to no-op when next export is set. This worked before 3.0.0, which introduced a lot of changes around next config handling to support the breaking changes in next@10.0.8, so we have a regression somewhere.

[jlengstorf]

just kidding! it still works. we were seeing this due to using an outdated version of the plugin 😅