Bump Scala patch versions

Updated to: 2.11.12, 2.12.20, 2.13.15

JAVA-5649

Author: rozza

.evergreen/.evg.yml

@@ -1857,11 +1857,11 @@ axes:
       - id: "2.12"
         display_name: "Scala 2.12"
         variables:
-          SCALA: "2.12.15"
+          SCALA: "2.12.20"
       - id: "2.13"
         display_name: "Scala 2.13"
         variables:
-          SCALA: "2.13.6"
+          SCALA: "2.13.15"
 
   # Choice of MongoDB storage engine
   - id: storage-engine

gradle.properties

@@ -16,7 +16,7 @@
 
 org.gradle.daemon=true
 org.gradle.jvmargs=-Duser.country=US -Duser.language=en
-scalaVersions=2.11.12,2.12.15,2.13.6
+scalaVersions=2.11.12,2.12.20,2.13.15
 defaultScalaVersions=2.13.6
 runOnceTasks=clean,release
 org.gradle.java.installations.auto-download=false