docs: upgrade Node.js to version 20

Node.js 20 is the current LTS release:
https://nodejs.org/en/about/releases/

BREAKING CHANGE: the minimum Node.js is 20

.github/workflows/build-and-release.yaml

@@ -207,6 +207,6 @@ jobs:
 
       - uses: actions/setup-node@v4
         with:
-          node-version: "18.x"
+          node-version: "20.x"
 
       - run: npx semantic-release

.github/workflows/pr-check_compliance.yaml

@@ -19,7 +19,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: "18.x"
+          node-version: "20.x"
       - uses: actions/cache@v3
         name: Cache dependencies
         with:

.github/workflows/pr-clang-format.yaml

@@ -16,7 +16,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: "18.x"
+          node-version: "20.x"
       - uses: actions/cache@v3
         name: Cache dependencies
         with:

.github/workflows/update-from-ncs.yaml

@@ -22,7 +22,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: actions/setup-node@v4
         with:
-          node-version: "18.x"
+          node-version: "20.x"
       - uses: actions/cache@v3
         name: Cache dependencies
         with:

package.json

@@ -32,7 +32,7 @@
     ]
   },
   "engines": {
-    "node": ">=18",
+    "node": ">=20",
     "npm": ">=9"
   },
   "release": {