Fix boost dependency

[Timple]

Without the -dev this happens in a docker install:

Starting >>> swri_console
--- stderr: swri_console                         
CMake Error at /usr/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:146 (message):
  Could NOT find Boost (missing: Boost_INCLUDE_DIR thread)
Call Stack (most recent call first):
  /usr/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:393 (_FPHSA_FAILURE_MESSAGE)
  /usr/share/cmake-3.16/Modules/FindBoost.cmake:2179 (find_package_handle_standard_args)
  CMakeLists.txt:24 (find_package)


---
Failed   <<< swri_console [1.65s, exited with code 1]

In practice this package is probably installed due to other packages already. But it's good to keep the dependencies in order.

[danthony06]

Thanks for the fix!