Add DocumenterVitepress to regression tests (#2670)

Author: asinghvi17

.github/workflows/regression-tests.yml

@@ -29,6 +29,7 @@ jobs:
           - package: 'Asciicast'
           - package: 'DocumenterPages'
           - package: 'DocumenterDescriptions'
+          - package: 'DocumenterVitepress'
     steps:
       - uses: actions/checkout@v5
       - uses: julia-actions/setup-julia@v2