[Noetic] nfc_ros fails to build: Missing dependecy rostest

[sloretz]

nfc_ros is failing to build on all platforms. It looks like it's missing a dependency on rostest

• https://build.ros.org/job/Nbin_uF64__nfc_ros__ubuntu_focal_amd64__binary/31/consoleFull
• https://build.ros.org/job/Nbin_ufhf_uFhf__nfc_ros__ubuntu_focal_armhf__binary/
• https://build.ros.org/job/Nbin_ufv8_uFv8__nfc_ros__ubuntu_focal_arm64__binary/

23:02:56 CMake Error at CMakeLists.txt:40 (find_package):
23:02:56   By not providing "Findrostest.cmake" in CMAKE_MODULE_PATH this project has
23:02:56   asked CMake to find a package configuration file provided by "rostest", but
23:02:56   CMake did not find one.
23:02:56 
23:02:56   Could not find a package configuration file provided by "rostest" with any
23:02:56   of the following names:
23:02:56 
23:02:56     rostestConfig.cmake
23:02:56     rostest-config.cmake
23:02:56 
23:02:56   Add the installation prefix of "rostest" to CMAKE_PREFIX_PATH or set
23:02:56   "rostest_DIR" to a directory containing one of the above files.  If
23:02:56   "rostest" provides a separate development package or SDK, be sure it has
23:02:56   been installed.