Merge pull request #878 from GSA/GSA/issue-877/dependabot-vulnerability

Update pa11y-ci library version and node version from 18 to 20.

Author: chitchcockkla

.github/workflows/frontend-tests.yaml

@@ -24,7 +24,7 @@ jobs:
       - name: Setup Node.js
         uses: actions/setup-node@v3
         with:
-          node-version: 18.x
+          node-version: 20.x
           cache: npm
           cache-dependency-path: training-front-end/package-lock.json
 

.nvmrc

@@ -1 +1 @@
-18
+20