Specify browser-sync version explicitly

[aminvakil]

BrowserSync/browser-sync#1682 (comment)

[aminvakil]

Without this change it fails with this error:

$ sudo gulp
/var/www/html/node_modules/micromatch/index.js:44
    let isMatch = picomatch(String(patterns[i]), { onResult, ...options }, true);
                                                             ^^^

SyntaxError: Unexpected token ...
    at createScript (vm.js:56:10)
    at Object.runInThisContext (vm.js:97:10)
    at Module._compile (module.js:549:28)
    at Object.Module._extensions..js (module.js:586:10)
    at Module.load (module.js:494:32)
    at tryModuleLoad (module.js:453:12)
    at Function.Module._load (module.js:445:3)
    at Module.require (module.js:504:17)
    at require (internal/module.js:20:19)
    at Object.<anonymous> (/var/www/html/node_modules/browser-sync/dist/public/stream.js:3:18)

[aminvakil]

World Cup 2022 is near and there was another thing which needed to be fixed :)

I've added the commit here, without this change, gulp command will fail.