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/kotlin-dsl/src/main/java/com/example/Library.java

@@ -0,0 +1,10 @@
+/*
+ * This Java source file was generated by the Gradle 'init' task.
+ */
+package com.example;
+
+public class Library {
+    public boolean someLibraryMethod() {
+        return true;
+    }
+}