Fixed grammar error

Change-Id: Ibe24197f309b756fcc3c9d17abb738e67e2b7990
Reviewed-on: https://weave-review.googlesource.com/1760
Reviewed-by: Vitaly Buka <vitalybuka@google.com>

README

diff --git a/README b/README
index 9b357a0..c78283b 100644
--- a/README
+++ b/README
@@ -1,6 +1,6 @@
 Overview
 --------
-libWeave is the library to with device side implementation of Weave
+libWeave is the library with device side implementation of Weave
 protocol.
 
 Sources