Remove prebuild.sh step

[WhitWaldo]

This script creates a file at src/version.ts which reflects the version value from package.json in the root. If one attempts to build the solution npx tsc --outDir ./build/ without running it, one gets errors showing that the module doesn't exist because the file isn't saved in the repo and only generated as part of this step.

This is less than ideal and should be corrected.