Update hero icons

[emilyvandewalle]

Hero icons recently released a v2 version, the blocks icon package is still based on the v1 version

Some notes:

• Some icons look quite different and the stroke width also changed from 2px to 1.5px
• Since we are using a couple of icons from other sets we'll have to see if these still match and maybe rework those a bit if needed (the icons added from the remix icon set and mono icons both have a 2px stroke width)
• Alternatively we could look into using a set that contains more technical/code/git icons like remix icons, feather icons, ... so we can rely more on 1 set