Bump pulumi/actions from 5 to 6

Bumps [pulumi/actions](https://github.com/pulumi/actions) from 5 to 6.
- [Release notes](https://github.com/pulumi/actions/releases)
- [Changelog](https://github.com/pulumi/actions/blob/main/CHANGELOG.md)
- [Commits](pulumi/actions@v5...v6)

---
updated-dependencies:
- dependency-name: pulumi/actions
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/pr.yml

@@ -50,7 +50,7 @@ jobs:
         with:
           dotnet-version: ${{ matrix.dotnet-version }}
       - name: Install Pulumi CLI
-        uses: pulumi/actions@v5
+        uses: pulumi/actions@v6
       - name: Build Pulumi SDK
         run: dotnet run build-sdk
       - name: Workspace clean (are xml doc file updates committed?)
@@ -85,7 +85,7 @@ jobs:
         with:
           go-version: 1.22.x
       - name: Install Pulumi CLI
-        uses: pulumi/actions@v5
+        uses: pulumi/actions@v6
       - name: Install netcoredbg (Linux)
         if: matrix.os == 'ubuntu-latest'
         run: |

.github/workflows/release-sdk.yml

@@ -48,7 +48,7 @@ jobs:
           dotnet-version: 8.0.x
           dotnet-quality: ga
       - name: Install Pulumi CLI
-        uses: pulumi/actions@v5
+        uses: pulumi/actions@v6
       - name: Build Pulumi SDK
         run: dotnet run build-sdk
       - name: Test Pulumi SDK