chore(test): run unit tests on node 18 and 20 (#57199)

Since we separated unit tests into its own job in PR #55621, we can now run unit tests against Node.js 18 and Node.js 20 (maintenance and lts) using a matrix.

Author: styfle

.github/workflows/build_and_test.yml

@@ -9,6 +9,7 @@ on:
 env:
   NAPI_CLI_VERSION: 2.14.7
   TURBO_VERSION: 1.10.9
+  NODE_MAINTENANCE_VERSION: 18
   NODE_LTS_VERSION: 20
   TEST_CONCURRENCY: 8
   # disable backtrace for test snapshots
@@ -164,9 +165,12 @@ jobs:
     name: test unit
     strategy:
       fail-fast: false
+      matrix:
+        node: [18, 20] # TODO: use env var like [env.NODE_MAINTENANCE_VERSION, env.NODE_LTS_VERSION]
 
     uses: ./.github/workflows/build_reusable.yml
     with:
+      nodeVersion: ${{ matrix.node }}
       skipForDocsOnly: 'yes'
       afterBuild: node run-tests.js -c ${TEST_CONCURRENCY} --type unit