Fix NuGet pack CI step: build in Release mode and exclude Benchmarks (#46)

## Summary
- Remove `--no-build` flag from pack command so it builds in Release
mode
- Exclude Benchmarks project from NuGet packing by setting
`IsPackable=false`

Fixes the CI failure from the previous NuGet pack PR.

## Changes
- Updated `.github/workflows/dotnet.yml` to use `dotnet pack -c Release`
instead of `dotnet pack --no-build`
- Added `<IsPackable>false</IsPackable>` to Benchmarks project file

## Test plan
- [ ] Verify the pack step now builds in Release mode
- [ ] Verify Benchmarks project is excluded from NuGet packages
- [ ] Verify CI passes on a subsequent build

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude <[email protected]>
Co-authored-by: Copilot <[email protected]>

Author: 3 people

.github/workflows/dotnet.yml

@@ -26,12 +26,12 @@ jobs:
     - name: Restore dependencies
       run: dotnet restore
     - name: Build
-      run: dotnet build --no-restore
+      run: dotnet build -c Release --no-restore
     - name: Test
-      run: dotnet test --no-build --verbosity normal
+      run: dotnet test -c Release --no-build --verbosity normal
     - name: Pack NuGet packages
       if: github.event_name != 'pull_request' && matrix.os == 'windows-latest'
-      run: dotnet pack --no-build --output nupkgs
+      run: dotnet pack -c Release --no-build --output nupkgs
     - name: Upload NuGet packages
       if: github.event_name != 'pull_request' && matrix.os == 'windows-latest'
       uses: actions/upload-artifact@v4

test/F23.StringSimilarity.Benchmarks/F23.StringSimilarity.Benchmarks.csproj

@@ -5,6 +5,7 @@
         <TargetFramework>net8.0</TargetFramework>
         <ImplicitUsings>enable</ImplicitUsings>
         <Nullable>enable</Nullable>
+        <IsPackable>false</IsPackable>
     </PropertyGroup>
 
     <ItemGroup>