fix: bad example in fast-foundation/src/accordion/README.md

[guimard]

🐛 Bug Report

When trying this example given in fast-foundation/saccordion/README.md with the current master branch, I got an error.

💻 Repro or Code Sample

Example from doc

import { Accordion, accordionTemplate as template } from "@microsoft/fast-foundation";
import { accordionStyles as styles } from "./my-accordion.styles";

export const myAccordion = Accordion.compose({
    baseName: "accordion",
    template,
    styles,
});

🤔 Expected Behavior

tsc success.

😯 Current Behavior

error TS2305: Module '"@microsoft/fast-foundation"' has no exported member 'Accordion'

🔦 Context

Trying to update jupyter-ui-toolkit

🌍 Your Environment

• OS & Device: Linux Debian