Set --release javac option to 8 (#1458)

* Set --release javac option to 8

* replace usage of var

modules/api/src/main/java/stryker4s/log/Logger.java

@@ -1,25 +1,28 @@
 package stryker4s.log;
 
 import java.util.function.Supplier;
+import java.util.Map;
 
 public interface Logger {
 
 	public void log(Level level, Supplier<String> msg);
 
 	public void log(Level level, Supplier<String> msg, Throwable t);
 
-  /** 
+	/**
 	 * Whether colors are enabled in the log
-    */
+	 */
 	public default boolean colorEnabled() {
-		var env = System.getenv();
-    // Explicitly disable color https://no-color.org/
-    boolean notNoColor = !env.containsKey("NO_COLOR");
-    // If there is a TERM on Linux (or Windows Git Bash), assume we support color
-    boolean unixEnabled = env.containsKey("TERM");
-    // On Windows there's no easy way. But if we're in Windows Terminal or ConEmu, we can assume we support color
-    boolean windowsEnabled = env.containsKey("WT_SESSION") || (System.getenv().containsKey("ConEmuANSI") && System.getenv("ConEmuANSI").equals("ON"));
+		Map<String, String> env = System.getenv();
+		// Explicitly disable color https://no-color.org/
+		boolean notNoColor = !env.containsKey("NO_COLOR");
+		// If there is a TERM on Linux (or Windows Git Bash), assume we support color
+		boolean unixEnabled = env.containsKey("TERM");
+		// On Windows there's no easy way. But if we're in Windows Terminal or ConEmu,
+		// we can assume we support color
+		boolean windowsEnabled = env.containsKey("WT_SESSION")
+				|| (System.getenv().containsKey("ConEmuANSI") && System.getenv("ConEmuANSI").equals("ON"));
 
-    return notNoColor && (unixEnabled || windowsEnabled);
+		return notNoColor && (unixEnabled || windowsEnabled);
 	}
 }

project/Settings.scala

@@ -88,7 +88,7 @@ object Settings {
     name := "stryker4s-api",
     crossPaths := false, // drop off Scala suffix from artifact names.
     autoScalaLibrary := false, // exclude scala-library from dependencies
-    javacOptions ++= Seq("--release", "11")
+    javacOptions ++= Seq("--release", "8")
   )
 
   lazy val testkitSettings: Seq[Setting[?]] = Seq(