Update Scala versions (#424)

Author: sideeffffect

src/main/scala/com/github/sideeffffect/sbtdecentscala/DecentScalaPlugin.scala

@@ -28,9 +28,9 @@ object DecentScalaPlugin extends AutoPlugin {
   }
 
   trait DecentScala {
-    def decentScalaVersion3 = "3.3.3"
-    def decentScalaVersion213 = "2.13.13"
-    def decentScalaVersion212 = "2.12.19" // scala-steward:off
+    def decentScalaVersion3 = "3.3.4"
+    def decentScalaVersion213 = "2.13.15"
+    def decentScalaVersion212 = "2.12.20" // scala-steward:off
     def decentScalaVersion211 = "2.11.12"
     def decentScalaSettings: List[Def.Setting[_]] =
       List(