Downgrade grunt-browserify

I couldn't correct the issue with peerDependencies. Maybe in the future.
Lock grunt-browserify in 2.0.8
Fix modules update

Updated every module to its latest version. Browserify is the only one not updated.
Add post "BrowserSync: browsers sincronizados"
Merge branch 'feature/update-packages' into content/browserSync-1
Optimize gif images

Gif images are too tricky to optimize in a fully automated script. Used ezgif.com to perform the optimization
Update post with default image