Chore: [AEA-0000] - udptae gitignore for gh-pages (#51)

## Summary

- Routine Change

### Details

- update .gitignore file to include gh-pages files

Author: anthony-nhs

.gitignore

@@ -38,3 +38,7 @@ build/
 src/main/resources/package/*.tgz
 _site/
 node_modules/
+.sass-cache
+.jekyll-cache
+.jekyll-metadata
+vendor