Adjust Github Actions Build Reference

[phutelmyer]

Describe the change
This change removes the preexisting daily build for Strelka in favor of the new nightly build.
This change also modifies the reference for the Build Status on the README.

Describe testing procedures
N/A

Sample output
N/A

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of and tested my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings