Merge pull request #876 from basil/jsr305

Stop using EOL JSR 305 annotation

Author: jglick

lib/src/main/java/com/cloudbees/groovy/cps/impl/ContinuationGroup.java

@@ -21,7 +21,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.function.Function;
-import javax.annotation.CheckReturnValue;
+import edu.umd.cs.findbugs.annotations.CheckReturnValue;
 import org.codehaus.groovy.runtime.InvokerInvocationException;
 import org.codehaus.groovy.runtime.ScriptBytecodeAdapter;
 import org.codehaus.groovy.runtime.callsite.CallSite;