Updated link in ee_utils_get_crs_web to use the GitHub URL for spatialreference.org data.

[MarShaikh]

This PR solves #363.

Summary

This PR addresses an issue with the ee_print function in the rgee package, which fails when attempting to retrieve metadata for some(?) image collections due to deprecated spatial reference URL. The error occurs when spatialreference.org is down, and the code attempts to fallback to the web archive, which is no longer supported. This PR modifies the ee_utils_get_crs_web function to use a GitHub backup for spatial reference data instead.

I did not write a test for this as there were no prior tests written for this function. However, I am happy to write a new test if necessary. Please feel free to correct any issues or let me to know which ones to address as well.

Thank you.