Add job for clang build

[christophfroehlich]

See ros-controls/realtime_tools#207

clang was complaining about implicit conversions in the PID class.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 93.93939% with 2 lines in your changes missing coverage. Please review.

Project coverage is 74.78%. Comparing base (93955a8) to head (483a788).

Files with missing lines	Patch %	Lines
include/control_toolbox/low_pass_filter.hpp	0.00%	0 Missing and 1 partial ⚠️
src/pid_ros.cpp	50.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           ros2-master     #239   +/-   ##
============================================
  Coverage        74.78%   74.78%           
============================================
  Files               22       22           
  Lines             1071     1071           
  Branches            85       85           
============================================
  Hits               801      801           
  Misses             222      222           
  Partials            48       48           

Flag	Coverage Δ
unittests	74.78% <93.93%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
test/pid_tests.cpp	100.00% <100.00%> (ø)
include/control_toolbox/low_pass_filter.hpp	76.19% <0.00%> (ø)
src/pid_ros.cpp	72.41% <50.00%> (ø)

[saikishor]

The changes look good to me. The clang job seem to fail due to the implicit conversions in the tests

[saikishor]

Looks perfect!