fix metapacakge suffix

Author: Misha-133

.github/workflows/dotnet.yml

@@ -101,7 +101,7 @@ jobs:
 
         - name: Generate Suffix
           if: env.IsTagBuild == 'true'
-          run: echo "Suffix=nightly.$(date +'%Y%m%d').${{ github.run_number }}" >> $GITHUB_ENV
+          run: echo "Suffix=-nightly.$(date +'%Y%m%d').${{ github.run_number }}" >> $GITHUB_ENV
 
         - name: setup NuGet
           uses: nuget/setup-nuget@v2
@@ -115,7 +115,7 @@ jobs:
             path: ${{ env.ArtifactStagingDirectory }}
 
         - name: Pack Metapackage
-          run: nuget pack "src/Discord.Net/Discord.Net.nuspec" -OutputDirectory ${{ env.ArtifactStagingDirectory }} -NonInteractive -p "suffix=-${{ env.Suffix }}"
+          run: nuget pack "src/Discord.Net/Discord.Net.nuspec" -OutputDirectory ${{ env.ArtifactStagingDirectory }} -NonInteractive -p "suffix=${{ env.Suffix }}"
 
         - name: Set API Keys
           run: |