chore: import upstream snapshot with attribution

contributing/samples/workflows/sequence/README.md

@@ -0,0 +1,39 @@
+# ADK Workflow Sequence Sample
+
+## Overview
+
+This sample demonstrates how to create a simple sequential workflow with **ADK Workflows**.
+
+It connects two LLM agents in a chain. The first agent (`generate_fruit_agent`) is instructed to return the name of a random fruit. The output of this agent becomes the input for the second agent (`generate_benefit_agent`), which then tells a health benefit about that specific fruit.
+
+In a sequence, the execution flows unconditionally from one node to the next in the order they are defined.
+
+## Sample Inputs
+
+This sample does not require any input to run.
+
+## Graph
+
+```mermaid
+graph TD
+    START --> generate_fruit_agent
+    generate_fruit_agent --> generate_benefit_agent
+```
+
+## How To
+
+1. Define the agents or functions that will make up the steps in your sequence.
+
+   ```python
+   generate_fruit_agent = Agent(...)
+   generate_benefit_agent = Agent(...)
+   ```
+
+1. Pass a tuple of three or more elements to `edges` to define an unconditional sequence starting from the first element and passing through each subsequent node in order.
+
+   ```python
+   Workflow(
+       name="root_agent",
+       edges=[("START", generate_fruit_agent, generate_benefit_agent)],
+   )
+   ```