Update INSPIRE-HEP icon to the current one
Their current favicon is just i.
![image](https://user-images.githubusercontent.com/92218586/138641677-313dbae4-afbc-43fd-86c9-e84f16e983c0.png)
their current twitter logo is
![image](https://user-images.githubusercontent.com/92218586/140744914-eafd1283-3d07-4631-9073-1ce1ff820e0f.png)
either of them will be Ok for the icon.


The one on academicons is an old version.
![image](https://user-images.githubusercontent.com/92218586/138641782-968d9b13-61bf-4e6c-9289-a59b71f670c7.png)

