Align scala-reflect version with Scala version in the project.
Align scala-reflect version with Scala version in the project.

This way spire build supports cross-versioning against multiple versions of
Scala properly.

adampingel/spire,codeaudit/spire,woparry/spire,non/spire,kevinmeredith/spire,kevinmeredith/spire,guersam/spire,AlecZorab/spire,non/spire,JackSullivan/spire,siddhartha-gadgil/spire,JackSullivan/spire,siddhartha-gadgil/spire,tixxit/spire,adampingel/spire,woparry/spire,rklaehn/spire,codeaudit/spire,rklaehn/spire,tixxit/spire,AlecZorab/spire,guersam/spire