Update docs deps, CI actions, and Maven plugins

Bump several developer dependencies and CI/tooling: update docs TypeScript to ~6.0.2 (and refresh docs/package-lock.json), upgrade GitHub Pages actions in .github/workflows/docs.yml (actions/configure-pages -> v6, actions/deploy-pages -> v5). In Maven files, bump spring-boot in mjml-java-spring to 4.0.5 and update plugin versions for spotbugs and spotless in the root pom. These changes bring dependency and tool versions up-to-date for compatibility and maintenance; the package-lock was regenerated to reflect updated resolved versions.

Author: jcputney

.github/workflows/docs.yml

@@ -43,7 +43,7 @@ jobs:
         run: npm run build
 
       - name: Setup Pages
-        uses: actions/configure-pages@v5
+        uses: actions/configure-pages@v6
 
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v4
@@ -59,4 +59,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v4
+        uses: actions/deploy-pages@v5