[Build] Update to Node 20 and remove 16 (EOL) (#7260)

attempt one

.circleci/config.yml

@@ -237,8 +237,8 @@ workflows:
   overall-circleci-commit-status: #These jobs run on every commit
     jobs:
       - lint:
-          name: node16-lint
-          node-version: lts/gallium
+          name: node20-lint
+          node-version: lts/iron
       - unit-test:
           name: node18-chrome
           node-version: lts/hydrogen
@@ -256,8 +256,8 @@ workflows:
   the-nightly: #These jobs do not run on PRs, but against master at night
     jobs:
       - unit-test:
-          name: node16-chrome-nightly
-          node-version: lts/gallium
+          name: node20-chrome-nightly
+          node-version: lts/iron
       - unit-test:
           name: node18-chrome
           node-version: lts/hydrogen

.github/workflows/pr-platform.yml

@@ -22,7 +22,7 @@ jobs:
           - macos-latest
           - windows-latest
         node_version:
-          - lts/gallium
+          - lts/iron
           - lts/hydrogen
         architecture:
           - x64

package.json

@@ -126,7 +126,7 @@
     "url": "https://github.com/nasa/openmct.git"
   },
   "engines": {
-    "node": ">=16.19.1 <20"
+    "node": ">=18.14.2 <22"
   },
   "browserslist": [
     "Firefox ESR",