build: make ci testing conditional on engines field in package.json, move configs to Node 12 (#1418) (#195)

* build: make ci testing conditional on engines field in package.json, move configs to Node 12

Co-authored-by: Benjamin E. Coe <bencoe@google.com>
Source-Link: googleapis/synthtool@2800f5a
Post-Processor: gcr.io/cloud-devrel-public-resources/owlbot-nodejs:latest@sha256:dc7bfb4c4bf50496abbdd24bd9e4aaa833dc75248c0a9e3a7f807feda5258873

Author: gcf-owl-bot[bot]

.github/.OwlBot.lock.yaml

@@ -13,5 +13,5 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-nodejs:latest
-  digest: sha256:f74e740638e66be7ced1540626217dbb72980eb73885b2339a70592f38c9ff2c
-# created: 2022-04-06T18:36:33.987617127Z
+  digest: sha256:dc7bfb4c4bf50496abbdd24bd9e4aaa833dc75248c0a9e3a7f807feda5258873
+# created: 2022-04-14T17:36:54.629564643Z

.github/workflows/ci.yaml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        node: [10, 12, 14, 16]
+        node: [10, 12, 14]
     steps:
       - uses: actions/checkout@v3
       - uses: actions/setup-node@v3