Use engines.node as source of version data for "actions/setup-node" action

The "actions/setup-node" GitHub Actions action is used to set up Node.js in the GitHub Actions runner machine.

The action supports obtaining the Node.js version to set up from the `engines.node` key of the package.json file.

This allows us to define the standardized version of Node.js for use by project contributors in a single place rather
than having to maintain multiple instances of that data.

Author: per1234

.github/workflows/check-markdown-task.yml

@@ -1,10 +1,6 @@
 # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/check-markdown-task.md
 name: Check Markdown
 
-env:
-  # See: https://github.com/actions/setup-node/#readme
-  NODE_VERSION: 16.x
-
 # See: https://docs.github.com/actions/using-workflows/events-that-trigger-workflows
 on:
   create:
@@ -77,7 +73,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v5
         with:
-          node-version: ${{ env.NODE_VERSION }}
+          node-version-file: package.json
 
       - name: Initialize markdownlint-cli problem matcher
         uses: xt0rted/markdownlint-problem-matcher@v3
@@ -105,7 +101,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v5
         with:
-          node-version: ${{ env.NODE_VERSION }}
+          node-version-file: package.json
 
       - name: Install Task
         uses: arduino/setup-task@v2

.github/workflows/check-prettier-formatting-task.yml

@@ -1,10 +1,6 @@
 # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/check-prettier-formatting-task.md
 name: Check Prettier Formatting
 
-env:
-  # See: https://github.com/actions/setup-node/#readme
-  NODE_VERSION: 16.x
-
 # See: https://docs.github.com/actions/using-workflows/events-that-trigger-workflows
 on:
   create:
@@ -242,7 +238,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v5
         with:
-          node-version: ${{ env.NODE_VERSION }}
+          node-version-file: package.json
 
       - name: Install Task
         uses: arduino/setup-task@v2

.github/workflows/check-taskfiles.yml

@@ -1,10 +1,6 @@
 # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/check-taskfiles.md
 name: Check Taskfiles
 
-env:
-  # See: https://github.com/actions/setup-node/#readme
-  NODE_VERSION: 16.x
-
 # See: https://docs.github.com/actions/using-workflows/events-that-trigger-workflows
 on:
   create:
@@ -77,7 +73,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v5
         with:
-          node-version: ${{ env.NODE_VERSION }}
+          node-version-file: package.json
 
       - name: Download JSON schema for Taskfiles
         id: download-schema

.github/workflows/check-workflows-task.yml

@@ -1,10 +1,6 @@
 # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/check-workflows-task.md
 name: Check Workflows
 
-env:
-  # See: https://github.com/actions/setup-node/#readme
-  NODE_VERSION: 16.x
-
 # See: https://docs.github.com/actions/using-workflows/events-that-trigger-workflows
 on:
   push:
@@ -38,7 +34,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v5
         with:
-          node-version: ${{ env.NODE_VERSION }}
+          node-version-file: package.json
 
       - name: Install Task
         uses: arduino/setup-task@v2

.github/workflows/sync-labels-npm.yml

@@ -1,12 +1,6 @@
 # Source: https://github.com/arduino/tooling-project-assets/blob/main/workflow-templates/sync-labels-npm.md
 name: Sync Labels
 
-env:
-  # See: https://github.com/actions/setup-node/#readme
-  NODE_VERSION: 16.x
-  CONFIGURATIONS_FOLDER: .github/label-configuration-files
-  CONFIGURATIONS_ARTIFACT_PREFIX: label-configuration-file-
-
 # See: https://docs.github.com/actions/using-workflows/events-that-trigger-workflows
 on:
   push:
@@ -27,6 +21,10 @@ on:
   workflow_dispatch:
   repository_dispatch:
 
+env:
+  CONFIGURATIONS_FOLDER: .github/label-configuration-files
+  CONFIGURATIONS_ARTIFACT_PREFIX: label-configuration-file-
+
 jobs:
   check:
     runs-on: ubuntu-latest
@@ -40,7 +38,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v5
         with:
-          node-version: ${{ env.NODE_VERSION }}
+          node-version-file: package.json
 
       - name: Download JSON schema for labels configuration file
         id: download-schema
@@ -138,7 +136,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v5
         with:
-          node-version: ${{ env.NODE_VERSION }}
+          node-version-file: package.json
 
       - name: Merge label configuration files
         run: |

package-lock.json

@@ -6,5 +6,8 @@
     "markdown-link-check": "^3.13.7",
     "markdownlint-cli": "^0.37.0",
     "prettier": "^3.6.2"
+  },
+  "engines": {
+    "node": "16.x"
   }
 }