Attempt to fix CI for earlier node versions.

Node hardcodes its default TLS certificates, meaning older versions do
not support the root certificate currently used by LetsEncrypt.

Use --use-openssl-ca to enable the use of the system's OpenSSL
certificates.

Since node v7 doesn't support NODE_OPTIONS, conditionally modify the
test script with sed.

.github/workflows/build.yml

@@ -73,8 +73,12 @@ jobs:
       - name: Run smoke tests
         env:
           SERPAPI_TEST_KEY: ${{ secrets.SERPAPI_TEST_KEY }}
+          NODE_OPTIONS: --use-openssl-ca
         run: |
           cd smoke_tests/commonjs
+          if [ "$(node -v)" == "v7.10.1" ]; then
+            sed -i.orig -e 's/node commonjs.js/node --use-openssl-ca commonjs.js/' package.json
+          fi
           npm i
           npm test