Fix wrong JDK version in README.md.

deltaspike/parent/pom.xml states <java.version>1.8</java.version>.

Signed-off-by: Juri Berlanda <juriberlanda@hotmail.com>
diff --git a/README.md b/README.md
index 1fa667d..410a0b7 100644
--- a/README.md
+++ b/README.md
@@ -37,7 +37,7 @@
 ## Requirements to Build
 
 - Git
-- JDK 6
+- JDK 8
 - Maven
 
 Just run `mvn clean install` from the top level directory, `deltaspike` to build the source code.
\ No newline at end of file