Document Python dependency

[stevage]

It appears that Python is a dependency for installing this, at least on macOS, because of sqlite3.

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npm ERR! gyp info ok
npm ERR! gyp info it worked if it ends with ok
npm ERR! gyp info using node-gyp@10.0.1
npm ERR! gyp info using node@18.19.0 | darwin | arm64
npm ERR! gyp info spawn make
npm ERR! gyp info spawn args [ 'BUILDTYPE=Release', '-C', 'build' ]
npm ERR! /bin/sh: python: command not found
npm ERR! make: *** [Release/obj/gen/sqlite-autoconf-3260000/sqlite3.c] Error 127
npm ERR! gyp ERR! build error
npm ERR! gyp ERR! stack Error: `make` failed with exit code: 2
npm ERR! gyp ERR! stack at ChildProcess.<anonymous> (/Users/stevebennett/.nvm/versions/node/v18.19.0/lib/node_modules/npm/node_modules/node-gyp/lib/build.js:209:23)
npm ERR! gyp ERR! System Darwin 22.6.0
...