Fix GHRepository#listWorkflows() and add a test

src/main/java/org/kohsuke/github/GHWorkflowsIterable.java

@@ -0,0 +1,53 @@
+package org.kohsuke.github;
+
+import java.net.MalformedURLException;
+import java.util.Iterator;
+
+import javax.annotation.Nonnull;
+
+/**
+ * Iterable for workflows listing.
+ */
+class GHWorkflowsIterable extends PagedIterable<GHWorkflow> {
+    private final transient GHRepository owner;
+
+    private GHWorkflowsPage result;
+
+    public GHWorkflowsIterable(GHRepository owner) {
+        this.owner = owner;
+    }
+
+    @Nonnull
+    @Override
+    public PagedIterator<GHWorkflow> _iterator(int pageSize) {
+        try {
+            GitHubRequest request = owner.getRoot()
+                    .createRequest()
+                    .withUrlPath(owner.getApiTailUrl("actions/workflows"))
+                    .build();
+
+            return new PagedIterator<>(
+                    adapt(GitHubPageIterator
+                            .create(owner.getRoot().getClient(), GHWorkflowsPage.class, request, pageSize)),
+                    null);
+        } catch (MalformedURLException e) {
+            throw new GHException("Malformed URL", e);
+        }
+    }
+
+    protected Iterator<GHWorkflow[]> adapt(final Iterator<GHWorkflowsPage> base) {
+        return new Iterator<GHWorkflow[]>() {
+            public boolean hasNext() {
+                return base.hasNext();
+            }
+
+            public GHWorkflow[] next() {
+                GHWorkflowsPage v = base.next();
+                if (result == null) {
+                    result = v;
+                }
+                return v.getWorkflows(owner);
+            }
+        };
+    }
+}