Update Webpack to use more secure hashing routines

[PeterHaughie]

When using node 18 the wpstart and wpbuild scripts bail with errors:

npm run wpstart

> barebones@0.1.0 wpstart
> wptheme-scripts wpstart

Browser Refresh Server ready.
Error: error:0308010C:digital envelope routines::unsupported
    at new Hash (node:internal/crypto/hash:67:19)
    at Object.createHash (node:crypto:133:10)
    at module.exports (/Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/webpack/lib/util/createHash.js:135:53)
    at NormalModule._initBuildHash (/Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/webpack/lib/NormalModule.js:417:16)
    at handleParseError (/Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/webpack/lib/NormalModule.js:471:10)
    at /Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/webpack/lib/NormalModule.js:503:5
    at /Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/webpack/lib/NormalModule.js:358:12
    at /Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/loader-runner/lib/LoaderRunner.js:373:3
    at iterateNormalLoaders (/Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/loader-runner/lib/LoaderRunner.js:214:10)
    at iterateNormalLoaders (/Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/loader-runner/lib/LoaderRunner.js:221:10)
    at /Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/loader-runner/lib/LoaderRunner.js:236:3
    at runSyncOrAsync (/Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/loader-runner/lib/LoaderRunner.js:130:11)
    at iterateNormalLoaders (/Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/loader-runner/lib/LoaderRunner.js:232:2)
    at Array.<anonymous> (/Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/loader-runner/lib/LoaderRunner.js:205:4)
    at Storage.finished (/Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/enhanced-resolve/lib/CachedInputFileSystem.js:55:16)
    at /Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/enhanced-resolve/lib/CachedInputFileSystem.js:91:9
/Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/@devloco/react-scripts-wptheme/scripts/wpstart.js:19
  throw err;
  ^

Error: error:0308010C:digital envelope routines::unsupported
    at new Hash (node:internal/crypto/hash:67:19)
    at Object.createHash (node:crypto:133:10)
    at module.exports (/Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/webpack/lib/util/createHash.js:135:53)
    at NormalModule._initBuildHash (/Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/webpack/lib/NormalModule.js:417:16)
    at /Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/webpack/lib/NormalModule.js:452:10
    at /Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/webpack/lib/NormalModule.js:323:13
    at /Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/loader-runner/lib/LoaderRunner.js:367:11
    at /Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/loader-runner/lib/LoaderRunner.js:233:18
    at context.callback (/Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/loader-runner/lib/LoaderRunner.js:111:13)
    at /Users/peterhaughie/Projects/tm2022-2/wp-content/themes/tm-2023/react-src/node_modules/@devloco/react-scripts-wptheme/node_modules/babel-loader/lib/index.js:55:103
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
  opensslErrorStack: [ 'error:03000086:digital envelope routines::initialization error' ],
  library: 'digital envelope routines',
  reason: 'unsupported',
  code: 'ERR_OSSL_EVP_UNSUPPORTED'
}

This is due to the webpack using the SHA512 hash which has been replaced in Webpack5 with xxhash64. The solutions are either to update the Webpack version to 5 and methodically go through all of the webpack build scripts to fix the breaking API changes or to try and enforce a different hashing algorithm in Webpack4 with something along the lines of:

module.exports = {
  //...
  experiments: {
    futureDefaults: true,
  },
};

module.exports = {
  //...
  output: {
    hashFunction: require('metrohash').MetroHash64,
  },
};

https://webpack.js.org/configuration/output/#outputhashfunction

https://webpack.js.org/configuration/experiments/#experimentsfuturedefaults