Update README.md

Fix typo
my-iss-574-fix
Merge pull request #576 from rcrovella/iss-574-fix

my-iss-574-fix
Assume push_macro & pop_macro require at least gcc 4.5.0.
Fixes #575
Merge branch '1.8.0' of github.com:thrust/thrust into 1.8.0
Merge pull request #577 from thrust/1.8.0

1.8.0
Annotate all functions which dereference an iterator in thrust::system::detail::sequential with __thrust_hd_warning_disable__
Merge pull request #579 from jaredhoberock/issue-578

Annotate all functions which dereference an iterator in thrust::system::...
Merge pull request #580 from thrust/1.8.0

1.8.0
Derive device iterator categories from
detail::iterator_category_with_system_and_traversal to satisfy libc++'s
implementation of std::iterator_traits' requirement that iterator
categories be convertible to standard iterator categories.

Fixes #581
Merge pull request #583 from jaredhoberock/issue-581

Derive device iterator categories from
Merge pull request #584 from thrust/1.8.0

1.8.0
Merge branch 'master' of https://github.com/thrust/thrust