Update Visible Assertions dependency to 2.1.0 (#488)

* Update Visible Assertions dependency to 2.1.0 to remove risk of dependency clashes with JNR-POSIX

Author: rnorth

CHANGELOG.md

@@ -8,6 +8,7 @@ All notable changes to this project will be documented in this file.
 ### Changed
 - Make Network instances reusable (i.e. work with `@ClassRule`) ([\#469](https://github.com/testcontainers/testcontainers-java/issues/469))
 - Added support for explicitly setting file mode when copying file into container ([\#446](https://github.com/testcontainers/testcontainers-java/issues/446), [\#467](https://github.com/testcontainers/testcontainers-java/issues/467)) 
+- Use Visible Assertions 2.1.0 for pre-flight test output (eliminating Jansi/JNR-POSIX dependencies for lower likelihood of conflict. JNA is now used internally by Visible Assertions instead).
 - Mark all links functionality as deprecated. This is pending removal in a later release. Please see [\#465](https://github.com/testcontainers/testcontainers-java/issues/465). {@link Network} features should be used instead.
 
 ## [1.4.3] - 2017-10-14

core/pom.xml

@@ -92,7 +92,7 @@
         <dependency>
             <groupId>org.rnorth.visible-assertions</groupId>
             <artifactId>visible-assertions</artifactId>
-            <version>2.0.0</version>
+            <version>2.1.0</version>
         </dependency>
 
         <!-- Test dependencies -->