fix copy-paste (#1043)

src/Microsoft.Tye.Core/ConfigModel/ConfigApplication.cs

@@ -118,8 +118,8 @@ namespace Microsoft.Tye.ConfigModel
 
                 foreach (var envVar in service.Configuration)
                 {
-                    context = new ValidationContext(service);
-                    if (!Validator.TryValidateObject(service, context, results, validateAllProperties: true))
+                    context = new ValidationContext(envVar);
+                    if (!Validator.TryValidateObject(envVar, context, results, validateAllProperties: true))
                     {
                         throw new TyeYamlException(
                             $"Environment variable '{envVar.Name}' of service '{service.Name}' validation failed." + Environment.NewLine +
@@ -129,8 +129,8 @@ namespace Microsoft.Tye.ConfigModel
 
                 foreach (var volume in service.Volumes)
                 {
-                    context = new ValidationContext(service);
-                    if (!Validator.TryValidateObject(service, context, results, validateAllProperties: true))
+                    context = new ValidationContext(volume);
+                    if (!Validator.TryValidateObject(volume, context, results, validateAllProperties: true))
                     {
                         throw new TyeYamlException(
                             $"Volume '{volume.Source}' of service '{service.Name}' validation failed." + Environment.NewLine +