BAEL-282 - Grep in Java after code review (#903)

* BAEL-242 Package refactoring after code review for article Grep in Java

* BAEL-282 Updated readme file

core-java/src/test/java/com/baeldung/grep/GrepWithUnix4JTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.java8.unix.grep;
+package com.baeldung.grep;
 
 import java.io.File;
 import java.util.List;