wiki error on VSCE link

[mixmix]

Page: https://github.com/EclipseFdn/open-vsx.org/wiki/Publishing-Extensions

has a link to vsce which is wrong:

• broken link : https://www.npmjs.com/package/vsce
• correct link : https://www.npmjs.com/package/@vscode/vsce

[kineticsquid]

Fixed, thanks!