Avoid duplication of tools list

Relates to #583, #613

Summary

Find a way to avoid the duplication of the list of tools between .tool-versions:

Lines 3 to 4 in 137070d

    
           actionlint 1.6.22 
        
           shellcheck 0.9.0

and nightly.yml:

Lines 33 to 34 in 137070d

    
           - actionlint 
        
           - shellcheck