Change to avoid docker pull rate limit issues in GitHub Actions

[MarcHagen]

• Fix for Optional PHP version check #19

We're running into Docker Hub rate limits, causing our GitHub Action runs to fail. This update changes the script to skip update checks if pulling fails, which helps prevent these failures and keeps the build process running smoothly.

Changes:

• Skip PHP version check if pulling the base image fails.
• Set PHP memory limit directly in the Dockerfile using echo 'memory_limit=4G' to avoid needing an external file. This removes the dependency on a local php-build.ini file.

Tested these changes in our fork, and builds complete successfully even when rate limits are hit.
We are running this for almost a half-year or so.
This helped make our CI process more reliable.

Thanks for reviewing! 🚀

[g105b]

This all makes sense, and looks like a nice addition for self-hosted runners, which I don't have that much experience with.

Thank you for your contribution - I hope it helps you and others in the future.