Update base version to 3.0

[Ian Lynagh]

On Sun, Oct 07, 2007 at 08:09:35AM -0700, Donald Bruce Stewart wrote:
> The base version in the 6.8 and head branch is behind the 6.6.1 branch.
> This seems likely to be true of a bunch of other core libraries. It
> means we can't reliably use cabal configurations to describe cabal files
> that build with both old and new ghc's.
> 
> [base in 6.8 and head branch should be version 3.0

Applied to both HEAD and 6.8 branches.


Thanks
Ian