Update scalafmt-core to 3.8.6 (#310)

Co-authored-by: ptrdom-scala-steward[bot] <157643620+ptrdom-scala-steward[bot]@users.noreply.github.com>

Author: ptrdom-scala-steward[bot]

.scalafmt.conf

@@ -1,3 +1,3 @@
-version = 3.8.5
+version = 3.8.6
 runner.dialect=scala212source3
 lineEndings=preserve