Upgrade SBT version to latest 0.13.13. Don't use deprecated <<= operator.

Author: gslowikowski

build.sbt

@@ -27,13 +27,11 @@ releasePublishArtifactsAction := PgpKeys.publishSigned.value
 
 releaseCrossBuild := false
 
-publishTo <<= version {
-  (v: String) =>
-    val nexus = "https://oss.sonatype.org/"
-    if (v.trim.endsWith("SNAPSHOT"))
-      Some("snapshots" at nexus + "content/repositories/snapshots")
-    else
-      Some("releases" at nexus + "service/local/staging/deploy/maven2")
+publishTo := {
+  if (isSnapshot.value)
+    Some("snapshots" at "https://oss.sonatype.org/content/repositories/snapshots")
+  else
+    Some("releases" at "https://oss.sonatype.org/service/local/staging/deploy/maven2")
 }
 
 pomExtra := {

project/build.properties

@@ -1 +1 @@
-sbt.version=0.13.12
+sbt.version=0.13.13