[feature] add new mock client

internal/pkg/mail/mail.go

@@ -0,0 +1,16 @@
+package mail
+
+import (
+	"context"
+
+	"github.com/google/uuid"
+
+	"base/pkg/email"
+)
+
+func (c client) Send(ctx context.Context, params email.Request) (*email.Response, error) {
+	return &email.Response{
+		ID:     uuid.NewString(),
+		Status: "Success",
+	}, nil
+}