Update dependency versions in readme.

Author: heuermh

README.md

@@ -12,9 +12,9 @@
 Install
 
  * JDK 1.8 or later, http://openjdk.java.net
- * Apache Maven 3.3.9 or later, http://maven.apache.org
- * Apache Spark 3.0.0 or later, http://spark.apache.org
- * ADAM: Genomic Data System 0.32.0 or later, https://github.com/bigdatagenomics/adam
+ * Apache Maven 3.6.3 or later, http://maven.apache.org
+ * Apache Spark 3.0.1 or later, http://spark.apache.org
+ * ADAM: Genomic Data System 0.33.0 or later, https://github.com/bigdatagenomics/adam
 
 To build
 
@@ -35,10 +35,10 @@ Welcome to
       ____              __
      / __/__  ___ _____/ /__
     _\ \/ _ \/ _ `/ __/  '_/
-   /___/ .__/\_,_/_/ /_/\_\   version 2.4.5
+   /___/ .__/\_,_/_/ /_/\_\   version 3.0.1
       /_/
 
-Using Scala version 2.11.12 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_191)
+Using Scala version 2.12.8 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_191)
 Type in expressions to have them evaluated.
 Type :help for more information.