chore: install redocly

Author: MaggieKimani1

.github/workflows/validate-descriptions.yml

@@ -30,6 +30,9 @@ jobs:
       with:
         submodules: recursive
 
+    - name: Install Redocly CLI
+      run: npm install -g @redocly/cli
+
     - name: Validate description with redocly
       run: |
         FILE="test/Microsoft.OpenAPI.OData.Reader.Tests/Resources/${{ matrix.descriptions }}"