[ci] bump actions versions to silence warnings; add node 20 to the matrix

Author: restjohn

.github/workflows/gh-pages-deploy.yml

@@ -1,7 +1,7 @@
 name: GH Pages Deploy
 
 on:
-  workflow_dispatch: 
+  workflow_dispatch:
   push:
     branches:
       - master

.github/workflows/run-tests.yml

@@ -9,12 +9,12 @@ jobs:
 
     strategy:
       matrix:
-        node-version: [14.x, 16.x, 18.x]
+        node-version: [14.x, 16.x, 18.x, 20.x]
 
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v4
     - name: Use Node.js ${{ matrix.node-version }}
-      uses: actions/setup-node@v1
+      uses: actions/setup-node@v4
       with:
         node-version: ${{ matrix.node-version }}
     - name: npm install, build, and test
@@ -29,7 +29,7 @@ jobs:
         JOB_CONTEXT: ${{ toJson(matrix) }}
       run: echo "$JOB_CONTEXT"
     - name: Coveralls
-      if: matrix.node-version == '14.x'
+      if: matrix.node-version == '20.x'
       uses: coverallsapp/github-action@master
       with:
         github-token: ${{ secrets.GITHUB_TOKEN }}