Update GitHub Actions workflows. (#343)

This PR was automatically generated by the
update-native-provider-workflows workflow in the pulumi/ci-mgmt repo,
from commit e7696dfaff0baa5b84126fc6971cc40e89d490cf.

.github/workflows/pull-request.yml

@@ -50,11 +50,11 @@ jobs:
     name: comment-on-pr
     steps:
     - name: Checkout Repo
-      uses: actions/checkout@v4
+      uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
       with:
         lfs: true
     - name: Comment PR
-      uses: thollander/actions-comment-pull-request@v2
+      uses: thollander/actions-comment-pull-request@fabd468d3a1a0b97feee5f6b9e499eab0dd903f6 # v2.5.0
       with:
         message: >
           PR is now waiting for a maintainer to run the acceptance tests.