Remove .SRCINFO (and old .AURINFO) from .gitignore

As of AUR 4.0.0 contributors have to maintain a GIT repository per project; .SRCINFO files need to be included in those

ArchLinuxPackages.gitignore

@@ -6,9 +6,5 @@
 *.log.*
 *.sig
 
-# AUR metadata
-.AURINFO
-.SRCINFO
-
 pkg/
 src/