DOC-3520: Upgrade configure-aws-credentials to v6 (#4249)

Fix OIDC role assumption hangs when GitHub forces Node 20 actions
onto Node 24 runners in preview workflows.

Author: kemister85

.github/workflows/preview_create.yml

@@ -52,7 +52,7 @@ jobs:
         mv ./build/docs/sitemap.xml ./build/docs/antora-sitemap.xml
 
     - name: configure aws credentials
-      uses: aws-actions/configure-aws-credentials@v5.0.0
+      uses: aws-actions/configure-aws-credentials@v6
       with:
         role-to-assume: arn:aws:iam::327995277200:role/staging-tinymce-docs-update
         role-session-name: tinymce-docs-update

.github/workflows/preview_delete.yml

@@ -33,7 +33,7 @@ jobs:
         node-version: 24
 
     - name: configure aws credentials
-      uses: aws-actions/configure-aws-credentials@v5.0.0
+      uses: aws-actions/configure-aws-credentials@v6
       with:
         role-to-assume: arn:aws:iam::327995277200:role/staging-tinymce-docs-update
         role-session-name: tinymce-docs-delete