Update to the latest clirr-maven-plugin

This fixes the issue with bcel 6.0-SNAPSHOT no longer being resolvable,
as reported with #450, and also #442

Note that the clirr-maven-plugin is currently only available in their
staging repo, once it's released the additional plugin repo can be
removed again.

See also mojohaus/clirr-maven-plugin#19

Closes #450

pom-main.xml

@@ -64,7 +64,7 @@
 			<plugin>
 				<groupId>org.codehaus.mojo</groupId>
 				<artifactId>clirr-maven-plugin</artifactId>
-				<version>2.6.1</version>
+				<version>2.8</version>
 				<executions>
 					<!-- Automatically run clirr:check on compile -->
 					<execution>
@@ -116,15 +116,6 @@
 						</difference>
 					</ignored>
 				</configuration>
-				<!-- prevent "clirr-maven-plugin:2.6.1:check failed: Invalid byte tag in constant pool: 18" -->
-				<!-- once 6.0 is released, the apache-snapshots pluginRepository can be removed as well -->
-				<dependencies>
-					<dependency>
-						<groupId>org.apache.bcel</groupId>
-						<artifactId>bcel</artifactId>
-						<version>6.0-SNAPSHOT</version>
-					</dependency>
-				</dependencies>
 			</plugin>
 		</plugins>
 	</build>
@@ -135,16 +126,16 @@
 			<plugin>
 				<groupId>org.codehaus.mojo</groupId>
 				<artifactId>clirr-maven-plugin</artifactId>
-				<version>2.6.1</version>
+				<version>2.8</version>
 			</plugin>
 		</plugins>
 	</reporting>
 
 	<pluginRepositories>
 		<pluginRepository>
-			<id>apache-snapshots</id>
-			<name>apache snapshots repo</name>
-			<url>https://repository.apache.org/content/repositories/snapshots</url>
+			<id>sonatype-clirr-staging</id>
+			<name>clirr staging repo</name>
+			<url>https://oss.sonatype.org/service/local/repositories/orgcodehausmojo-1069/content/</url>
 		</pluginRepository>
 	</pluginRepositories>