update and rename lab

.gitlab-ci.yml

 A:
-    script: /testers/cs2/lab08/suite/test
+    script: /testers/cs2/lab06/suite/test

.idea/misc.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_11" project-jdk-name="11" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_19" default="true" project-jdk-name="19" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
 </project>
\ No newline at end of file

.idea/modules.xml

@@ -2,7 +2,7 @@
 <project version="4">
   <component name="ProjectModuleManager">
     <modules>
-      <module fileurl="file://$PROJECT_DIR$/lab08.iml" filepath="$PROJECT_DIR$/lab08.iml" />
+      <module fileurl="file://$PROJECT_DIR$/lab06.iml" filepath="$PROJECT_DIR$/lab06.iml" />
     </modules>
   </component>
 </project>
\ No newline at end of file

.idea/runConfigurations/A_Tests.xml

 <component name="ProjectRunConfigurationManager">
   <configuration default="false" name="A Tests" type="JUnit" factoryName="JUnit">
-    <module name="lab08" />
+    <module name="lab06" />
     <option name="MAIN_CLASS_NAME" value="" />
     <option name="METHOD_NAME" value="" />
     <option name="TEST_OBJECT" value="tags" />

.idea/vcs.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file

src/edu/caltech/cs2/lab08/PebblingGraph.java → src/edu/caltech/cs2/lab06/PebblingGraph.java

-package edu.caltech.cs2.lab08;
+package edu.caltech.cs2.lab06;
 
 import java.util.*;
 import java.util.stream.Collectors;
@@ -42,6 +42,6 @@ public class PebblingGraph {
     }
 
     public List<Integer> toposort() {
-        return null;
+        return new ArrayList<Integer>();
     }
 }
\ No newline at end of file

tests/edu/caltech/cs2/lab08/PebblesTests.java → tests/edu/caltech/cs2/lab06/PebblesTests.java

-package edu.caltech.cs2.lab08;
+package edu.caltech.cs2.lab06;
 
 import org.junit.jupiter.api.*;
 
-import edu.caltech.cs2.lab08.PebblingGraph.PebblingNode;
+import edu.caltech.cs2.lab06.PebblingGraph.PebblingNode;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.CsvSource;