fix: add required pubkey for 1.25.5

[allan2]

Roman's key is necessary to build for nginx 1.25.5.

You can verify the key is legitimate through:

wget https://nginx.org/download/nginx-1.25.5.tar.gz
wget https://nginx.org/download/nginx-1.25.5.tar.gz.asc
gpg --verify nginx-1.25.5.tar.gz.asc

It is also here: https://keyserver.ubuntu.com/pks/lookup?search=43387825DDB1BB97EC36BA5D007C8D7C15D87369&fingerprint=on&op=index

Checklist

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• I have written my commit messages in the Conventional Commits format.
• I have read the CONTRIBUTING doc
• I have added tests (when possible) that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto master
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

[dekobon]

Thank you for the contribution!