Rename ign to gz in LuxCore demo.

[iche033]

🦟 Bug fix

Summary

Fix luxcore demo by renaming ign to gz and updating its gz library dep versions.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov]

Codecov Report

Merging #781 (2c578b3) into gz-rendering7 (0937b2a) will not change coverage.
The diff coverage is n/a.

@@              Coverage Diff               @@
##           gz-rendering7     #781   +/-   ##
==============================================
  Coverage          75.53%   75.53%           
==============================================
  Files                164      164           
  Lines              14382    14382           
==============================================
  Hits               10864    10864           
  Misses              3518     3518           

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