Add Scala 2.13.0-RC1 support

- upgrade Scala version from 2.13.0-M5 to 2.13.0-RC1 in `build.sbt` and `.travis.yml`

- upgrade scalatest version from 3.0.6-SNAP4 to 3.0.8-RC2
- upgrade stala-xml version from 1.1.1 to 1.2.0

Some fixes in tests were required:

- 's' and 'raw' string interpolators are now implemented as macros and macros are not instrumented; 's"Hello, $name"' expression was changed to explicit strings concatenation '"Hello, " + name' so the number of instrumented statements is the same in all Scala versions
see:
scala/scala@0cebcdf#diff-648e8f7f409d844c3c99b2d5a0d0dfe5R94
scala/scala#7779

- special symbol for all compilation phases was changed from "all" to "_"
see:
scala/scala@4d29431#diff-d686e8e67add4d42682f22193d20494bR1246
scala/scala#7908

.travis.yml

@@ -10,7 +10,7 @@ scala:
   - 2.10.7
   - 2.11.12
   - 2.12.8
-  - 2.13.0-M5
+  - 2.13.0-RC1
 
 before_cache:
   - find "$HOME/.sbt/" -name '*.lock' -print0 | xargs -0 rm

build.sbt

@@ -6,12 +6,12 @@ import sbtcrossproject.CrossProject
 import sbtcrossproject.CrossType
 
 val Org = "org.scoverage"
-val ScalatestVersion = "3.0.6-SNAP4"
+val ScalatestVersion = "3.0.8-RC2"
 
 val appSettings = Seq(
     organization := Org,
     scalaVersion := "2.12.8",
-    crossScalaVersions := Seq("2.10.7", "2.11.12", "2.12.8", "2.13.0-M5"),
+    crossScalaVersions := Seq("2.10.7", "2.11.12", "2.12.8", "2.13.0-RC1"),
     fork in Test := false,
     publishMavenStyle := true,
     publishArtifact in Test := false,
@@ -43,6 +43,11 @@ val appSettings = Seq(
             <name>Stephen Samuel</name>
             <url>http://github.com/sksamuel</url>
           </developer>
+          <developer>
+            <id>gslowikowski</id>
+            <name>Grzegorz Slowikowski</name>
+            <url>http://github.com/gslowikowski</url>
+          </developer>
         </developers>
     },
     pomIncludeRepository := {
@@ -97,7 +102,7 @@ lazy val plugin = Project("scalac-scoverage-plugin", file("scalac-scoverage-plug
       libraryDependencies ++= {
         CrossVersion.partialVersion(scalaVersion.value) match {
           case Some((2, scalaMajor)) if scalaMajor > 10 =>
-            Seq("org.scala-lang.modules" %% "scala-xml" % "1.1.1")
+            Seq("org.scala-lang.modules" %% "scala-xml" % "1.2.0")
           case _ =>
             Seq()
         }

scalac-scoverage-plugin/src/test/scala/scoverage/PluginCoverageTest.scala

@@ -14,7 +14,7 @@ class PluginCoverageTest
     compiler.compileCodeSnippet( """ object DefaultArgumentsObject {
                                    |  val defaultName = "world"
                                    |  def makeGreeting(name: String = defaultName): String = {
-                                   |    s"Hello, $name"
+                                   |    "Hello, " + name
                                    |  }
                                    |} """.stripMargin)
     assert(!compiler.reporter.hasErrors)

scalac-scoverage-plugin/src/test/scala/scoverage/ScoverageCompiler.scala

@@ -21,7 +21,7 @@ object ScoverageCompiler {
 
   def settings: Settings = {
     val s = new scala.tools.nsc.Settings
-    s.Xprint.value = List("all")
+    s.Xprint.value = List("all", "_")
     s.deprecation.value = true
     s.Yrangepos.value = true
     s.Yposdebug.value = true