Declare dependency on libatomic in package.xml

[cottsay]

This library is used here:

iceoryx/iceoryx_utils/CMakeLists.txt

Lines 187 to 189 in c4270c9

	if(LINUX)
	set(ICEORYX_PLATFORM ${CMAKE_CURRENT_SOURCE_DIR}/platform/linux/)
	target_link_libraries(iceoryx_utils PRIVATE acl atomic ${CODE_COVERAGE_LIBS})

Here are the backing rosdep rules for libatomic: https://github.com/ros/rosdistro/blob/master/rosdep/base.yaml#L1856-L1861

The library is somehow implicitly installed for our Ubuntu builds, but it needs an explicit dependency for RHEL: https://build.ros2.org/job/Rbin_rhel_el864__iceoryx_utils__rhel_8_x86_64__binary/5/console

[codecov]

Codecov Report

Merging #689 (70ed271) into master (c4270c9) will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #689      +/-   ##
==========================================
+ Coverage   74.52%   74.54%   +0.01%     
==========================================
  Files         317      317              
  Lines       11224    11224              
  Branches     1970     1970              
==========================================
+ Hits         8365     8367       +2     
+ Misses       2081     2079       -2     
  Partials      778      778              

Flag	Coverage Δ
unittests	74.50% <ø> (+0.01%)	⬆️
unittests_timing	31.18% <ø> (-0.02%)	⬇️

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

Impacted Files	Coverage Δ
iceoryx_utils/source/posix_wrapper/timer.cpp	59.64% <0.00%> (-0.88%)	⬇️
..._utils/source/posix_wrapper/unix_domain_socket.cpp	58.52% <0.00%> (+1.84%)	⬆️