Switch to ESM for source and test, use CommonJS for dist (#806)

.github/workflows/test.yml

@@ -38,7 +38,7 @@ jobs:
           npm run all
       - name: Check all jobs are in all-tests-passed.needs
         run: |
-          tsc check-all-tests-passed-needs.ts
+          tsc --module nodenext --moduleResolution nodenext --target es2022 check-all-tests-passed-needs.ts
           node check-all-tests-passed-needs.js
         working-directory: .github/scripts
       - name: Make sure no changes from linters are detected

.github/workflows/update-known-checksums.yml

@@ -20,11 +20,12 @@ jobs:
           persist-credentials: true
       - uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6.3.0
         with:
-          node-version: "20"
+          node-version-file: .nvmrc
+          cache: npm
       - name: Update known checksums
         id: update-known-checksums
         run:
-          node dist/update-known-checksums/index.js
+          node dist/update-known-checksums/index.cjs
           src/download/checksum/known-checksums.ts
       - name: Check for changes
         id: changes-exist