Update to 5.x (#23)

This PR aims to upgrade Cucumber dependency to 5.X, actually 5.6.0.

**Content:**
- update code to be compatible with Cucumber 5.6.0
- added some tests (mainly copied from Cucumber Java)
- add documentation in README about major changes:
  - move all classes under `io.cucumber.scala` to be more consistent with Cucumber Java
  - parameters change in Before/After hooks to be consistent with Cucumber Java
- upgrade Scala versions, Scala Maven plugin and Groovy

The breaking changes are open to discussion but I feel:
- it helps convey the idea that there is major changes with the upcoming 5.x release (I would like to include the fix for #1 as well, PR coming soon...)
- it makes Cucumber Scala more consistent with Cucumber Java and will ease developers to contribute

Author: gaeljw

README.md

@@ -24,3 +24,44 @@ To use cucumber-jvm-scala in your project, add the following dependency to your
     <scope>test</scope>
 </dependency>
 ```
+
+## Compatibility matrix
+
+The Cucumber Scala version matches the Cucumber version except for the bugfix number
+which can be different.
+
+| Cucumber Scala version | Cucumber version | Scala versions   |
+|------------------------|------------------|------------------|
+| 5.6.0                  | 5.6.0            | 2.11, 2.12, 2.13 |
+| 4.7.1                  | 4.7.1            | 2.11, 2.12, 2.13 |
+
+## Migrating from 4.x to 5.x
+
+If you are using Cucumber Scala 4.7.x and want to upgrade to 5.x, please note there are some major changes in addition to the Cucumber upgrade itself.
+
+### Packages
+
+All Cucumber Scala classes are now under `io.cucumber.scala` package instead of `cucumber.api.scala`.
+
+### Before/BeforeStep/After/AfterStep definitions
+
+The `Before`, `BeforeStep`, `After` and `AfterStep` definitions have slightly changed:
+- to apply only with some tags, the variable list of tags as `String*` is replaced by a single tag expression of type `String`.
+- if providing both an order and a tag expression, the order is now the second parameter instead of the first.
+This is more consistent with the Java implementation.
+
+For instance, the following code:
+
+```scala
+Before(1, "@tag1", "@tag2") { _ =>
+  // Do Something    
+}
+```
+
+Is replaced by:
+
+```scala
+Before("@tag1 or @tag2", 1) { _ =>
+  // Do Something    
+}
+```

examples/pom.xml

@@ -4,7 +4,7 @@
     <parent>
         <groupId>io.cucumber</groupId>
         <artifactId>cucumber-jvm-scala</artifactId>
-        <version>4.7.2-SNAPSHOT</version>
+        <version>5.6.0-SNAPSHOT</version>
     </parent>
 
     <artifactId>scala-examples</artifactId>

examples/src/test/scala/cucumber/examples/scalacalculator/RpnCalculatorStepDefinitions.scala

@@ -1,7 +1,6 @@
 package cucumber.examples.scalacalculator
 
-import cucumber.api.Scenario
-import cucumber.api.scala.{ScalaDsl, EN}
+import io.cucumber.scala.{EN, ScalaDsl, Scenario}
 import org.junit.Assert._
 
 class RpnCalculatorStepDefinitions extends ScalaDsl with EN {

examples/src/test/scala/cucumber/examples/scalacalculator/RunCukesTest.scala

@@ -1,8 +1,8 @@
 package cucumber.examples.scalacalculator
 
-import cucumber.api.CucumberOptions
+import io.cucumber.junit.{Cucumber, CucumberOptions}
 import org.junit.runner.RunWith
-import cucumber.api.junit.Cucumber
 
 @RunWith(classOf[Cucumber])
+@CucumberOptions()
 class RunCukesTest