fix: Only generate tsconfig.eslint.json if project is TS enabled.

[milesj]

to: @hayes

Title says it all. Also fixed .eslintcache since it's a file not a folder.

[airbnb-bot]

	Fails
🚫	Danger failed to run dangerfile.js.

Error Error

Cannot find module '/home/runner/work/nimbus/nimbus/node_modules/@airbnb/config-danger/lib/index.js'. Please verify that the package.json has a valid "main" entry
Error: Cannot find module '/home/runner/work/nimbus/nimbus/node_modules/@airbnb/config-danger/lib/index.js'. Please verify that the package.json has a valid "main" entry
    at tryPackage (internal/modules/cjs/loader.js:288:19)
    at Function.Module._findPath (internal/modules/cjs/loader.js:515:18)
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:759:27)
    at Function.Module._load (internal/modules/cjs/loader.js:677:27)
    at Function._module2.default._load (/home/runner/work/nimbus/nimbus/node_modules/override-require/dist/overrideRequire.js:43:25)
    at Module.require (internal/modules/cjs/loader.js:830:19)
    at require (internal/modules/cjs/helpers.js:68:18)
    at Object.<anonymous> (dangerfile.js:3:21)
    at Module._compile (internal/modules/cjs/loader.js:936:30)
    at Object.requireFromString [as default] (/home/runner/work/nimbus/nimbus/node_modules/require-from-string/index.js:28:4)

Dangerfile

----------------------^

Generated by 🚫 dangerJS against def1780