Change mailing list names in README

An underscore is used in the mailing list names rather than a dash, so it is
parallel_libs instead of parallel-libs.

llvm-svn: 273742
GitOrigin-RevId: babc13a3e25636bd6b9ee64baf42bca1a8e497cf
diff --git a/README.rst b/README.rst
index 5fe9517..4ab6981 100644
--- a/README.rst
+++ b/README.rst
@@ -82,8 +82,8 @@
 ----------------------------------------------
 Two mailing lists will be set up for the project:
 
-1. parallel-libs-dev@lists.llvm.org for discussions among project developers, and
-2. parallel-libs-commits@lists.llvm.org for patches and commits to the project.
+1. parallel_libs-dev@lists.llvm.org for discussions among project developers, and
+2. parallel_libs-commits@lists.llvm.org for patches and commits to the project.
 
 Each subproject library will manage its own components in Bugzilla. So, for
 example, there can be several Bugzilla components for different parts of