cmake: fix pkg-config in static mode

Change-Id: Ic2397eee6ea67fc5d0b76ce77bbd8e000f90177c
diff --git a/Dockerfile b/Dockerfile
index 10b4cd7..e55cd95 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -6,7 +6,7 @@
         cppunit-dev gnutls-dev jsoncpp-dev \
         argon2-dev openssl-dev fmt-dev \
         http-parser-dev asio-dev msgpack-cxx-dev \
-        readline-dev
+        readline-dev yaml-cpp-dev libunistring-dev
 
 # Build restinio
 RUN mkdir restinio && cd restinio \