Add support for Cucumber 6.11.0

As raised in #6, we cannot build against Cucumber 6.11.0, as it requires
a new version of `cucumber-messages` which is incompatible with our
`gherkin` dependency.

To allow us to migrate to the new version, we need to make sure that we
align both versions.

Closes #6.

pom.xml

@@ -43,9 +43,9 @@
 		<java.version>1.8</java.version>
 		<maven.compile.source>1.8</maven.compile.source>
 		<maven.compile.target>1.8</maven.compile.target>
-		<cucumber.version>6.10.2</cucumber.version>
+		<cucumber.version>6.11.0</cucumber.version>
 		<cucumber.reporting.version>5.5.3</cucumber.reporting.version>
-		<gherkin.version>17.0.2</gherkin.version>
+		<gherkin.version>18.0.0</gherkin.version>
 		<maven.site.skip>true</maven.site.skip>
 		<maven.site.deploy.skip>true</maven.site.deploy.skip>
 	</properties>