Update tests and README after official Humble release

[christophebedard]

Follow-up to #741

Relates to #738

setup-ros-docker images for Humble were recently added: ros-tooling/setup-ros-docker#51

Signed-off-by: Christophe Bedard bedard.christophe@gmail.com

[codecov]

Codecov Report

Merging #749 (85dc98a) into master (6f31f68) will not change coverage.
The diff coverage is n/a.

❗ Current head 85dc98a differs from pull request most recent head de32f19. Consider uploading reports for the commit de32f19 to get more accurate results

@@           Coverage Diff           @@
##           master     #749   +/-   ##
=======================================
  Coverage   49.61%   49.61%           
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  Files           2        2           
  Lines         262      262           
  Branches       68       68           
=======================================
  Hits          130      130           
  Misses        132      132           

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[christophebedard]

This is mostly test-related, so I'll just merge this.