ci: github-script: cope with V5 breaking changes

The actions/github-script was recently updated from v3.1.0 to v6
to catch Node 16 (f49acac), but
unfortunately there were breaking changes in the API with v5:

* https://github.com/actions/github-script#breaking-changes-in-v5
* actions/github-script#242 (comment)

Error was manifest as:

TypeError: Cannot read properties of undefined
           (reading 'listWorkflowRunArtifacts')

So update our code to to use the new way to do things.

issues: #62

Signed-off-by: Stephan Linz <[email protected]>

.github/workflows/doc-publish.yml

@@ -20,15 +20,15 @@ jobs:
         uses: actions/github-script@v6
         with:
           script: |
-            var artifacts = await github.actions.listWorkflowRunArtifacts({
+            var artifacts = await github.rest.actions.listWorkflowRunArtifacts({
                owner: context.repo.owner,
                repo: context.repo.repo,
                run_id: ${{ github.event.workflow_run.id }},
             });
             var matchArtifact = artifacts.data.artifacts.filter((artifact) => {
               return artifact.name == "doc"
             })[0];
-            var download = await github.actions.downloadArtifact({
+            var download = await github.rest.actions.downloadArtifact({
                owner: context.repo.owner,
                repo: context.repo.repo,
                artifact_id: matchArtifact.id,