Dockerfile showing error "failed to compute cache key: "/Pipfile.lock" not found"

Dockerfile :

FROM python:3.8-slim-buster
RUN apt-get update && 
 apt-get -y upgrade && 
 apt-get install -y --no-install-recommends make && 
 apt-get clean && 
 rm -rf /var/lib/apt/lists/* && 
 pip install --no-cache-dir --upgrade pip && 
 pip install --no-cache-dir pipenv

WORKDIR /sphinxtechnicalwriting

COPY Pipfile Pipfile.lock /sphinxtechnicalwriting/

RUN pipenv install --system --deploy

Error Displayed :

=> CANCELED [2/5] RUN apt-get update &&     apt-get -y upgrade &&     apt-get install -y --no-install-recommends make &&     apt-get clean &&       0.6s
 => CACHED [3/5] WORKDIR /sphinxtechnicalwriting                                                                                                     0.0s
 => ERROR [4/5] COPY Pipfile Pipfile.lock /sphinxtechnicalwriting/                                                                                   0.0s
------
 > [4/5] COPY Pipfile Pipfile.lock /sphinxtechnicalwriting/:
------
failed to compute cache key: "/Pipfile.lock" not found: not found

Tried clearing pipfile cache but now it gave cancelled in the 1st run command as well