Bump actions/setup-node from 4 to 6 (#88)

Author: dependabot[bot]

.github/workflows/build_documentation.yml

@@ -23,7 +23,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v5
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: "20"
           cache-dependency-path: "kit/package-lock.json"

.github/workflows/build_pr_documentation.yml

@@ -24,7 +24,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v5
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: "20"
           cache-dependency-path: "kit/package-lock.json"