• Updates package.json for publishing to NPM
  • Sets upgrades-core and defender-deploy-client-cli as optionalDependencies, since those are often run but not always required (for example if users do not run upgrade safety checks or Defender)
  • Updates the package name to @openzeppelin/foundry-upgrades
    • Users can use the package name as @openzeppelin/foundry-upgrades in their Solidity scripts/tests, but we leave the examples as openzeppelin-foundry-upgrades and use remappings to avoid confusion (since the same instructions are also used for Git submodules or Soldeer)
• Adds instructions for NPM and Soldeer installations
  • While OpenZeppelin Contracts (and Upgradeable Contracts) could also be installed with NPM or Soldeer, we omit that from the instructions to avoid further confusion, since the steps are already complex

Fixes #40