No such file or directory: 'requirements/dev.txt'

Docker Desktop for Mac
1

I have many answers posted for this issue, i.e., unable to locating the requirements.txt. However none of the suggestions worked for me. Is there anyone please help me find the solution?

Dockerfile

FROM python:3.7-slim
# Set environment varibles
ENV PYTHONDONTWRITEBYTECODE 1
ENV PYTHONUNBUFFERED 1

# Set work directory
WORKDIR /airproject

# Install dependencies
COPY Pipfile Pipfile.lock /airproject/
ADD requirements* /airproject/requirements/
RUN pip install -r requirements/dev.txt

# Copy project
COPY . /airproject/

When I run 'docker build .', it returns 'Could not open requirements file: [Errno 2] No such file or directory: 'requirements/dev.txt'’