Update storybook.yml to work with new yarn version

Author: jakeb-nhs

.github/workflows/storybook.yml

@@ -10,9 +10,20 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
+          
+      - name: Set up Node.js
+        uses: actions/setup-node@v2
+        with:
+          node-version: '18.x'
+          
+      - name: Enable corepack
+        run: corepack enable
+        
+      - name: Set Yarn version
+        run: yarn set version stable
 
       - name: Yarn Install
         run: yarn install