Clean up JUnit dependency management (#159)

* Add junit-bom to dependencyManagement section
* Remove explicit version from junit-xxx dependencies since they now
  are defined by the junit-bom
* Add junit-platform-commons and junit-platform-launcher which are
  direct dependencies of junit-pioneer
* Remove exclusions from junit-pioneer; they are no longer necessary
  because of the junit-bom

Closes #158

pom.xml

@@ -114,6 +114,23 @@
         <sonar.host.url>https://sonarcloud.io</sonar.host.url>
     </properties>
 
+    <dependencyManagement>
+
+        <dependencies>
+
+            <!-- ensure all JUnit dependencies have correct version from the JUnit BOM -->
+            <dependency>
+                <groupId>org.junit</groupId>
+                <artifactId>junit-bom</artifactId>
+                <version>${junit.jupiter.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+
+        </dependencies>
+
+    </dependencyManagement>
+
     <dependencies>
 
         <!-- required dependencies -->
@@ -152,21 +169,30 @@
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
-            <version>${junit.jupiter.version}</version>
             <scope>test</scope>
         </dependency>
 
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-engine</artifactId>
-            <version>${junit.jupiter.version}</version>
             <scope>test</scope>
         </dependency>
 
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-params</artifactId>
-            <version>${junit.jupiter.version}</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-commons</artifactId>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>org.junit.platform</groupId>
+            <artifactId>junit-platform-launcher</artifactId>
             <scope>test</scope>
         </dependency>
 
@@ -175,28 +201,6 @@
             <artifactId>junit-pioneer</artifactId>
             <version>${junit-pioneer.version}</version>
             <scope>test</scope>
-            <!-- Pioneer has typically been behind Jupiter's current version but still works.
-                 Keeping these exclusions in here until and unless they cause problems, and
-                 let Pioneer use whatever version of JUnit we are using.
-            -->
-            <exclusions>
-                <exclusion>
-                    <groupId>org.junit.jupiter</groupId>
-                    <artifactId>junit-jupiter-api</artifactId>
-                </exclusion>
-                <exclusion>
-                    <groupId>org.junit.jupiter</groupId>
-                    <artifactId>junit-jupiter-params</artifactId>
-                </exclusion>
-                <exclusion>
-                    <groupId>org.junit.platform</groupId>
-                    <artifactId>junit-platform-commons</artifactId>
-                </exclusion>
-                <exclusion>
-                    <groupId>org.junit.platform</groupId>
-                    <artifactId>junit-platform-launcher</artifactId>
-                </exclusion>
-            </exclusions>
         </dependency>
 
         <dependency>