[2.x] Deprecate url(...)

**Problem**
In sbt 2.x url already reaturns URI, but it's somewhat confusing.

**Solution**
Deprecate it instead.

sbt-app/src/main/scala/package.scala

@@ -39,6 +39,8 @@ package object sbt
   // IO
   def uri(s: String): URI = new URI(s)
   def file(s: String): File = new File(s)
+
+  @deprecated("Use uri(...) instead", "2.0.2")
   def url(s: String): URI = new URI(s)
   implicit def fileToRichFile(file: File): sbt.io.RichFile = new sbt.io.RichFile(file)
   implicit def filesToFinder(cc: Iterable[File]): sbt.io.PathFinder =