Update package-lock.json

 Dependabot cannot update normalize-url to a non-vulnerable version
The latest possible version that can be installed is 3.3.0 because of the following conflicting dependency:

react-scripts@3.0.1 requires normalize-url@^3.0.0 via a transitive dependency on postcss-normalize-url@4.0.1
The earliest fixed version is 4.5.1.

Author: websJC