Replace deprecated nuget task

azure/deploy.yml

@@ -9,19 +9,23 @@ steps:
     dotnet pack "src\Discord.Net.Analyzers\Discord.Net.Analyzers.csproj" --no-restore --no-build -v minimal -c $(buildConfiguration) -o "$(Build.ArtifactStagingDirectory)" /p:BuildNumber=$(buildNumber) /p:IsTagBuild=$(buildTag)
   displayName: Pack projects
 
-- task: NuGet@0
-  inputs:
-    command: pack
-    arguments: src/Discord.Net/Discord.Net.nuspec -OutputDirectory "$(Build.ArtifactStagingDirectory)" -properties suffix=""
+- task: NuGetCommand@2
   displayName: Pack metapackage (release mode)
   condition: eq(variables['buildTag'], True)
-
-- task: NuGet@0
   inputs:
-    command: pack
-    arguments: src/Discord.Net/Discord.Net.nuspec -OutputDirectory "$(Build.ArtifactStagingDirectory)" -properties suffix="-$(buildNumber)"
+    command: 'pack'
+    packagesToPack: 'src/Discord.Net/Discord.Net.nuspec'
+    versioningScheme: 'off'
+    buildProperties: 'suffix=""'
+
+- task: NuGetCommand@2
   displayName: Pack metapackage
   condition: eq(variables['buildTag'], False)
+  inputs:
+    command: 'pack'
+    packagesToPack: 'src/Discord.Net/Discord.Net.nuspec'
+    versioningScheme: 'off'
+    buildProperties: 'suffix="-$(buildNumber)"'
 
 - task: NuGetCommand@2
   displayName: Push to NuGet