Revert "Remove Node 12 from CI (#2306)" (#2309)

This reverts commit 23739db.

Author: prathmesh-stripe

.github/workflows/main.yml

@@ -63,9 +63,7 @@ jobs:
           - '18'
           - '16'
           - '14'
-          # Node subdependency(eslint-utils) added optional chaining syntax that does not work in v12
-          # TODO: https://jira.corp.stripe.com/browse/RUN_DEVSDK-1610
-          # - "12"
+          - '12'
     runs-on: ${{ matrix.os }}
     steps:
       - uses: extractions/setup-just@v2