Minor fixes to NGINX Plus Installation Guide.

[y82]

Proposed changes

This patch adds minor but useful fixes to the Install guide:

• the crt and key filenames are "nginx-repo", so they should be renamed after downloading similar to license.jwt
• if the repo file is modified, the repo update command (sudo apt update) needs to be done
• path to the nginx.conf file now specified for the 'License management' step
• 2 latest supported versions updated to R34 and R33

Checklist

Before merging a pull request, run through this checklist and mark each as complete.

• I have read the contributing guidelines
• I have signed the F5 Contributor License Agreement (CLA)
• I have rebased my branch onto main
• I have ensured my PR is targeting the main branch and pulling from my branch from my own fork
• I have ensured that the commit messages adhere to Conventional Commits
• I have ensured that documentation content adheres to the style guide
• If the change involves potentially sensitive changes¹, I have assessed the possible impact
• If applicable, I have added tests that prove my fix is effective or that my feature works
• I have ensured that existing tests pass after adding my changes
• If applicable, I have updated README.md and CHANGELOG.md

Footnotes

1. Potentially sensitive changes include anything involving code, personally identify information (PII), live URLs or significant amounts of new or revised documentation. Please refer to our style guide for guidance about placeholder content. ↩