CHANGELOG: update for 2.7 release

Signed-off-by: Jens Axboe <[email protected]>

CHANGELOG

@@ -11,6 +11,12 @@ liburing-2.7 release
 - Add 64-bit length variants of io_uring_prep_{m,f}advise()
 - Add BIND/LISTEN support and helpers / man pages
 - Add io_uring_enable_rings.3 man page
+- Fix bug in io_uring_prep_read_multishot()
+- Fixup bundle test cases
+- Add fixed-hugepage test case
+- Fix io_uring_prep_fixed_fd_install.3 man page
+- Note 'len' == 0 requirement in io_uring_prep_send.3 man page
+- Fix some test cases for skipping on older kernels
 
 liburing-2.6 release