add buildtool depend on pkg-config (#1)

http://build.ros.org/view/Ksrc_uX/job/Kbin_uX64__kinesis_manager__ubuntu_xenial_amd64__binary/1/console
Resolves:
15:41:49 CMake Error at /usr/share/cmake-3.5/Modules/FindPackageHandleStandardArgs.cmake:148 (message):
15:41:49   Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE)

rosdep key `pkg-config` https://github.com/ros/rosdistro/blob/master/rosdep/base.yaml#L4205

kinesis_manager/package.xml

@@ -12,6 +12,7 @@
 
 
   <buildtool_depend>cmake</buildtool_depend>
+  <buildtool_depend>pkg-config</buildtool_depend>
 
   <depend>aws_common</depend>
   <depend>curl</depend>