sbt 1.9.x support

sbt-coverter plugin fails when using sbt 1.9.x at this code:

Converter/sbt-converter/src/main/scala/org/scalablytyped/converter/plugin/ScalablyTypedPluginBase.scala

Lines 114 to 118 in 3a4686a

    
           case valid if valid.startsWith("1.8") => old(state) 
        
           case invalid => 
        
             sys.error( 
        
               s"This version of the ScalablyTyped plugin only supports 1.8.x. You're currently using $invalid", 
        
             )

java.lang.RuntimeException: This version of the ScalablyTyped plugin only supports 1.8.x. You're currently using 1.9.0
	at scala.sys.package$.error(package.scala:30)
	at org.scalablytyped.converter.plugin.ScalablyTypedPluginBase$.$anonfun$globalSettings$2(ScalablyTypedPluginBase.scala:117)

sbt 1.9.0 is almost compatible with sbt 1.8.x, so this version check logic needs to be updated.

Created a PR #540 as a fix for this

	case valid if valid.startsWith("1.8") => old(state)
	case invalid =>
	sys.error(
	s"This version of the ScalablyTyped plugin only supports 1.8.x. You're currently using $invalid",
	)