bug fix: updated warning message to reflect impending v1.0 release (spack#47887)

Author: carsonwoods

lib/spack/spack/schema/config.py

@@ -106,8 +106,8 @@
             {
                 "names": ["install_missing_compilers"],
                 "message": "The config:install_missing_compilers option has been deprecated in "
-                "Spack v0.23, and is currently ignored. It will be removed from config in "
-                "Spack v0.25.",
+                "Spack v0.23, and is currently ignored. It will be removed from config after "
+                "Spack v1.0.",
                 "error": False,
             },
         ],