Node compatibility

[markvideon]

The web project as-is appears to be incompatible with newer versions of Node. The code lab would benefit from comments to this effect.

Similar issue on another project described here:
auth0/node-jsonwebtoken#992

/home/wallet-web-codelab/web/node_modules/buffer-equal-constant-time/index.js:37
var origSlowBufEqual = SlowBuffer.prototype.equal;
                                  ^

TypeError: Cannot read properties of undefined (reading 'prototype')
    at Object.<anonymous> (/Users/markvideon/wallet-web-codelab/web/node_modules/buffer-equal-constant-time/index.js:37:35)
    at Module._compile (node:internal/modules/cjs/loader:1760:14)
    at Object..js (node:internal/modules/cjs/loader:1892:10)
    at Module.load (node:internal/modules/cjs/loader:1480:32)
    at Module._load (node:internal/modules/cjs/loader:1299:12)
    at TracingChannel.traceSync (node:diagnostics_channel:328:14)
    at wrapModuleLoad (node:internal/modules/cjs/loader:245:24)
    at Module.require (node:internal/modules/cjs/loader:1503:12)
    at require (node:internal/modules/helpers:152:16)
    at Object.<anonymous> (/Users/markvideon/wallet-web-codelab/web/node_modules/jwa/index.js:1:19)