remove uses of deprecated ResolverOptions.Client

`NewResolver` calls `NewDockerAuthorizer` and `ConfigureDefaultRegistries`,
both of which set the client if none is set;

https://github.com/containerd/containerd/blob/dd5e9f653813b3177c3b70ea03e20aaed397e1f9/remotes/docker/authorizer.go#L91-L99
https://github.com/containerd/containerd/blob/dd5e9f653813b3177c3b70ea03e20aaed397e1f9/remotes/docker/registry.go#L156-L174

Signed-off-by: Sebastiaan van Stijn <[email protected]>

Author: thaJeztah

client/llb/imagemetaresolver/resolver.go

@@ -45,7 +45,6 @@ func New(with ...ImageMetaResolverOpt) llb.ImageMetaResolver {
 	headers.Set("User-Agent", version.UserAgent())
 	return &imageMetaResolver{
 		resolver: docker.NewResolver(docker.ResolverOptions{
-			Client:  http.DefaultClient,
 			Headers: headers,
 		}),
 		platform: opts.platform,

util/contentutil/refs.go

@@ -20,7 +20,6 @@ func ProviderFromRef(ref string) (ocispecs.Descriptor, content.Provider, error)
 	headers := http.Header{}
 	headers.Set("User-Agent", version.UserAgent())
 	remote := docker.NewResolver(docker.ResolverOptions{
-		Client:  http.DefaultClient,
 		Headers: headers,
 	})
 
@@ -40,7 +39,6 @@ func IngesterFromRef(ref string) (content.Ingester, error) {
 	headers := http.Header{}
 	headers.Set("User-Agent", version.UserAgent())
 	remote := docker.NewResolver(docker.ResolverOptions{
-		Client:  http.DefaultClient,
 		Headers: headers,
 	})