Update Carter NuGet package references

Author: jchannon

src/Carter.ResponseNegotiators.Newtonsoft/Carter.ResponseNegotiators.Newtonsoft.csproj

@@ -20,7 +20,7 @@
 
     <ItemGroup>
         <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
-        <PackageReference Include="Carter" Version="6.1.1"/>
+        <PackageReference Include="Carter" Version="7.0.0-alpha1"/>
         <PackageReference Include="MinVer" Version="2.5.0">
             <PrivateAssets>all</PrivateAssets>
         </PackageReference>

test/Carter.ResponseNegotiators.Newtonsoft.Tests/Carter.ResponseNegotiators.Newtonsoft.Tests.csproj

@@ -4,7 +4,7 @@
 
     <ItemGroup>
         <PackageReference Include="MartinCostello.Logging.XUnit" Version="0.1.0"/>
-        <PackageReference Include="Carter" Version="6.1.1"/>
+        <PackageReference Include="Carter" Version="7.0.0-alpha1"/>
     </ItemGroup>