Use Hamcrest syntax for the compliance tests

Not sure why this wasn't the case already, my IDE complained about the syntax

Author: iconara

jmespath-core/src/test/java/io/burt/jmespath/JmesPathComplianceTest.java

@@ -18,7 +18,7 @@
 import org.junit.runner.RunWith;
 import org.hamcrest.Matcher;
 
-import static org.junit.Assert.assertTrue;
+import static org.hamcrest.Matchers.is;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.fail;
 import static org.hamcrest.Matchers.containsString;
@@ -72,9 +72,10 @@ public void run() {
         Expression<U> compiledExpression = runtime.compile(expression);
         U result = compiledExpression.search(input);
         if (expectedError == null) {
-          assertTrue(
+          assertThat(
             String.format("Expected <%s> to be <%s>, expression <%s> compiled expression <%s>", result, expectedResult, expression, compiledExpression),
-            runtime.compare(expectedResult, result) == 0
+            runtime.compare(expectedResult, result),
+            is(0)
           );
         } else {
           fail(String.format("Expected \"%s\" error", expectedError));