Moved workflow samples out of .github/workflows

The `.github/workflows` directory has additional permissions attached, preventing these
files from being by the Upgrade Gradle Wrapper plugin.

.github/workflow-samples/groovy-dsl/src/test/java/basic/BasicTest.java

@@ -0,0 +1,10 @@
+package basic;
+
+import org.junit.Test;
+
+public class BasicTest {
+    @Test
+    public void test() {
+        assert true;
+    }
+}