Base: Add .gitconfig to Git file icon files

This adds .gitconfig to git in the file icon provider.

Base/etc/FileIconProvider.ini

@@ -5,7 +5,7 @@ cplusplus=*.cpp,*.cxx,*.cc,*.c++
 c=*.c
 font=*.font
 form=*.frm
-git=*.gitignore,*.gitattributes,*.gitcredentials,*.mailmap,*.gitmodules
+git=*.gitignore,*.gitattributes,*.gitcredentials,*.mailmap,*.gitmodules,*.gitconfig
 header=*.h,*.hpp,*.hxx,*.hh,*.h++
 html=*.html,*.htm
 css=*.css