org.telegram.telegrambots.meta.exceptions.TelegramApiException: Bot token and username can't be empty

Question

I am working on Java Spring Boot project which includes simple Telegram Bot. My problem: I don't want to push credentials such as bot username and bot token to my remote repository. To achieve this, I simply put .env file into .gitignore, but without creds, Java CI can't build project. I get quite natural root exception: org.telegram.telegrambots.meta.exceptions.TelegramApiException: Bot token and username can't be empty

Here is the code of my bot:

import application.carsharingapp.exception.NotificationSendingException;
import application.carsharingapp.service.notification.NotificationService;
import io.github.cdimascio.dotenv.Dotenv;
import lombok.RequiredArgsConstructor;
import org.springframework.stereotype.Service;
import org.telegram.telegrambots.bots.TelegramLongPollingBot;
import org.telegram.telegrambots.meta.api.methods.send.SendMessage;
import org.telegram.telegrambots.meta.api.objects.Update;
import org.telegram.telegrambots.meta.exceptions.TelegramApiException;

@RequiredArgsConstructor
@Service
public class TelegramNotificationService extends TelegramLongPollingBot
        implements NotificationService {
    private static final Dotenv DOTENV = Dotenv.configure().ignoreIfMissing().load();
    private static final String BOT_USERNAME = DOTENV.get("BOT_USERNAME");
    private static final String BOT_TOKEN = DOTENV.get("BOT_TOKEN");
    private static final String TARGET_CHAT_ID = DOTENV.get("TARGET_CHAT_ID");

    @Override
    public void sendNotification(String message) {
        SendMessage sendMessage = new SendMessage();
        sendMessage.setText(message);
        sendMessage.setChatId(TARGET_CHAT_ID);
        try {
            execute(sendMessage);
        } catch (TelegramApiException e) {
            throw new NotificationSendingException("Can't send notification "
                    + "to chat: " + sendMessage.getChatId(), e);
        }
    }

    @Override
    public void onUpdateReceived(Update update) {
    }

    @Override
    public String getBotUsername() {
        return BOT_USERNAME;
    }

    @Override
    public String getBotToken() {
        return BOT_TOKEN;
    }
}

And here is code of my bot's config:

import application.carsharingapp.service.notification.impl.TelegramNotificationService;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.telegram.telegrambots.meta.TelegramBotsApi;
import org.telegram.telegrambots.meta.exceptions.TelegramApiException;
import org.telegram.telegrambots.updatesreceivers.DefaultBotSession;

@Configuration
public class TelegramBotConfig {
    @Bean
    public TelegramBotsApi telegramBotsApi(TelegramNotificationService telegramNotificationService)
            throws TelegramApiException {
        TelegramBotsApi api = new TelegramBotsApi(DefaultBotSession.class);
        api.registerBot(telegramNotificationService);
        return api;
    }
}

I would really like to hear some advice or tips on how to solve this problem and what are the possible solutions.

To solve this problem I tried to set some mock values for credentials, but that I got 404 Not found error