build(deps): bump brace-expansion from 1.1.18 to 1.1.21 - #893

Changed pages include:

• index.html - view
• 404.html - view
• blog/index.html - view
• case-studies/index.html - view
• docs/index.html - view
• job-center/index.html - view
• partners/index.html - view
• zh/index.html - view
• blog/archive/index.html - view
• blog/cncf-graduation-announcement/index.html - view

There are more changes not included in the list