[CI] use node 18, Python 3.11, update misc GitHub actions

It turns-out that building Theia works with Python 3.11 (same version
used in Theia workflows) but not with version 3.12.2 that was pulled
before (when we were requesting 3.x). With the later version, node-gyp
would error-out while attempting to build the Theia native dependencies.

Signed-off-by: Marc Dumais <marc.dumais@ericsson.com>

.github/workflows/main.yml

@@ -13,50 +13,49 @@ on:
 
 jobs:
   build:
-    name: ubuntu-latest,  Node.js 16.x
+    name: ubuntu-latest,  Node.js 18.x
 
     runs-on: ubuntu-latest
     timeout-minutes: 60
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
-      - name: Use Node.js "16.x"
-        uses: actions/setup-node@v1
+      - name: Use Node.js "18.x"
+        uses: actions/setup-node@v4
         with:
-          node-version: "16.x"
+          node-version: "18.x"
           registry-url: "https://registry.npmjs.org"
 
-      - name: Use Python 3.x
-        uses: actions/setup-python@v2
+      - name: Use Python 3.11
+        uses: actions/setup-python@v5
         with:
-          python-version: "3.x"
+          python-version: "3.11"
 
       - name: Build
         shell: bash
         run: |
           yarn
 
       - name: Checkout Theia
-        uses: actions/checkout@master
+        uses: actions/checkout@v4
         with:
           repository: eclipse-theia/theia
           path: ./theia
 
-      - name: Build Theia
+      - name: Build Theia browser example
         shell: bash
         working-directory: ./theia
         run: |
           yarn --skip-integrity-check --network-timeout 100000
           yarn browser build
 
-      - name: Run Theia
+      - name: Run Theia browser example
         shell: bash
         working-directory: ./theia
         run: yarn browser start &
 
       - name: Test (playwright)
-        uses: GabrielBB/xvfb-action@v1
-        with:
-          run: yarn ui-tests
+        shell: bash
+        run: yarn ui-tests