fix: compile to commonjs (#369)

Publishing `@guardian/cdk` in ESM format is tricky as additional tooling required by consumers such as [ts-node](TypeStrong/ts-node#1007) (see also [this](TypeStrong/ts-node#935)), [ESLint](eslint/rfcs#43) and [Jest](https://jestjs.io/docs/ecmascript-modules) have varying support.

It is easiest to stay on CommonJS.

We'll have to stay on v7.0.1 of `read-pkg-up` to achieve this; v8.0.0 doesn't bring any new features or fixes, so this is safe.

package.json

@@ -62,7 +62,7 @@
     "@aws-cdk/aws-s3": "1.94.1",
     "@aws-cdk/core": "1.94.1",
     "aws-sdk": "^2.868.0",
-    "read-pkg-up": "^8.0.0"
+    "read-pkg-up": "7.0.1"
   },
   "config": {
     "commitizen": {

src/constants/library-info.ts

@@ -1,6 +1,6 @@
-import { readPackageUpSync } from "read-pkg-up";
+import readPkgUp from "read-pkg-up";
 
-const version = readPackageUpSync({ cwd: __dirname })?.packageJson.version ?? "unknown";
+const version = readPkgUp.sync({ cwd: __dirname })?.packageJson.version ?? "unknown";
 
 export const LibraryInfo = {
   VERSION: version,

tsconfig.json

@@ -1,7 +1,7 @@
 {
   "compilerOptions": {
     "target": "ES2020",
-    "module": "ES2020",
+    "module": "commonjs",
     "moduleResolution": "node",
     "declaration": true,
     "declarationMap": true,