Update Node.js to version 20 (LTS)

Update GitHub action dependencies:
- `actions/checkout`
- `actions/setup-node`
- `actions/cache`
- `actions/upload-artifact`

.github/workflows/ci.yml

@@ -10,10 +10,10 @@ jobs:
         os:
           - ubuntu-latest
         node:
-          - '16'
+          - '20'
     steps:
-      - uses: actions/checkout@v3
-      - uses: actions/setup-node@v3
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
         with:
           node-version: ${{ matrix.node }}
       - run: npm install

.github/workflows/package.yml

@@ -5,10 +5,10 @@ jobs:
   package_linux:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
-    - uses: actions/setup-node@v3
+    - uses: actions/checkout@v4
+    - uses: actions/setup-node@v4
       with:
-        node-version: '16'
+        node-version: '20'
     - uses: actions/cache@v3
       with:
         path: ~/.npm
@@ -17,7 +17,7 @@ jobs:
           ${{ runner.os }}-node-
     - run: npm install
     - run: npm run package -- linux
-    - uses: actions/upload-artifact@v3
+    - uses: actions/upload-artifact@v4
       with:
         name: linux
         path: |
@@ -27,11 +27,11 @@ jobs:
   package_macos:
     runs-on: macos-latest
     steps:
-    - uses: actions/checkout@v3
-    - uses: actions/setup-node@v3
+    - uses: actions/checkout@v4
+    - uses: actions/setup-node@v4
       with:
-        node-version: '16'
-    - uses: actions/cache@v3
+        node-version: '20'
+    - uses: actions/cache@v4
       with:
         path: ~/.npm
         key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
@@ -39,7 +39,7 @@ jobs:
           ${{ runner.os }}-node-
     - run: npm install
     - run: npm run package -- darwin
-    - uses: actions/upload-artifact@v3
+    - uses: actions/upload-artifact@v4
       with:
         name: macos
         path: |
@@ -48,11 +48,11 @@ jobs:
   package_windows:
     runs-on: windows-latest
     steps:
-    - uses: actions/checkout@v3
-    - uses: actions/setup-node@v3
+    - uses: actions/checkout@v4
+    - uses: actions/setup-node@v4
       with:
-        node-version: '16'
-    - uses: actions/cache@v3
+        node-version: '20'
+    - uses: actions/cache@v4
       with:
         path: ~/.npm
         key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
@@ -60,7 +60,7 @@ jobs:
           ${{ runner.os }}-node-
     - run: npm install
     - run: npm run package -- win32
-    - uses: actions/upload-artifact@v3
+    - uses: actions/upload-artifact@v4
       with:
         name: windows
         path: |