aur/solr: Unknown PGP key

[Peter Nabbefeld <peter.nabbefeld@xxxxxx>]

Hello,

when trying to install the solr package from aur, installation fails 
because of an unknown PGP key ("051A0FAF76BC6507", according to comment 
should be "Adrien Grand (CODE SIGNING KEY) <jpountz@xxxxxxxxxx>").

Was this key removed from database for any reason, or did it just 
change? Or does the package have security issues, and I shouldn't 
install it?

Kind regards

Peter