Bump parser to 8.0.0 (graphql-dotnet#3042)

Author: Shane32

src/GraphQL/GraphQL.csproj

@@ -9,7 +9,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="GraphQL-Parser" Version="8.0.0-preview-140" />
+    <PackageReference Include="GraphQL-Parser" Version="8.0.0" />
     <PackageReference Include="Microsoft.CSharp" Version="4.7.0" />
     <PackageReference Include="NullabilityInfo" Version="1.0.7">
       <PrivateAssets>all</PrivateAssets>