Patches

• Make sure to not show pages/404 GIP error from _app having GIP: #10974
• Fix examples with relay-compiler: #10976
• Use core-js promise polyfill for nomodule browsers: #10985
• Improve Sass Error: #10982
• Add support for getStaticProps in pages/404: #10984

Credits

Huge thanks to @ijjk, @messa, and @timneutkens for helping!