Require Node.js >= 12.20, >= 14.13.1

Which added support for named exports for CJS via static analysis:
nodejs/node#35249
nodejs/node@1e8cb08edc for v15
nodejs/node@f551f52f83 for v14.13
nodejs/node@9eb1fa1924 for v12.20

This is also necessary for `node:` scheme support, checked by the
`unicorn/prefer-node-protocol` ESLint rule (currently disabled pending
support in eslint-plugin-node):
nodejs/node#35387
nodejs/node@ee9e3e75aa for v15
nodejs/node@91b820e939 for v14.13.1
nodejs/node@0f757bc2df for v12.20

Signed-off-by: Kevin Locke <kevin@kevinlocke.name>

.github/workflows/node.js.yml

@@ -69,7 +69,7 @@ jobs:
         - ubuntu-latest
         - windows-latest
         node:
-        - '12.17'
+        - '12.20'
         - '*'
         exclude:
         # Exclude os/version already run in test-primary

package.json

@@ -78,7 +78,7 @@
     "tmp-promise": "^3.0.2"
   },
   "engines": {
-    "node": ">=12.17",
+    "node": ">=12.20 || >=14.13.1",
     "npm": ">=1.3.7"
   },
   "david": {