Bump actions/setup-dotnet from 3 to 4 (pulumi#208)

Bumps [actions/setup-dotnet](https://github.com/actions/setup-dotnet) from 3 to 4.
- [Release notes](https://github.com/actions/setup-dotnet/releases)
- [Commits](actions/setup-dotnet@v3...v4)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/pr.yml

@@ -24,7 +24,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
       - name: Setup dotnet SDK v6.0
-        uses: actions/setup-dotnet@v3
+        uses: actions/setup-dotnet@v4
         with:
           dotnet-version: ${{ matrix.dotnet-version }}
       - name: Install Pulumi CLI
@@ -55,7 +55,7 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
       - name: Setup dotnet SDK v6.0
-        uses: actions/setup-dotnet@v3
+        uses: actions/setup-dotnet@v4
         with:
           dotnet-version: ${{ matrix.dotnet-version }}
       - name: Set up Go 1.19.x

.github/workflows/release-sdk.yml

@@ -43,7 +43,7 @@ jobs:
         with:
           ref: ${{ inputs.ref }}
       - name: Set up DotNet 6.0.x
-        uses: actions/setup-dotnet@v3
+        uses: actions/setup-dotnet@v4
         with:
           dotnet-version: 8.0.x
           dotnet-quality: ga