Update installation instructions

[iche033]

🦟 Bug fix

gazebosim/gazebo_test_cases#155

Summary

• Replaced ign with gz
• Updated windows instructions
• Updated ogre-next lib name

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 #906 (534658a) into gz-rendering8 (890cc29) will not change coverage.
The diff coverage is n/a.

❗ Current head 534658a differs from pull request most recent head 82cab51. Consider uploading reports for the commit 82cab51 to get more accurate results

@@              Coverage Diff               @@
##           gz-rendering8     #906   +/-   ##
==============================================
  Coverage          75.21%   75.21%           
==============================================
  Files                176      176           
  Lines              16839    16839           
==============================================
  Hits               12665    12665           
  Misses              4174     4174           

[ahcorde]

just a small nit