Install patched version of Poca.

Install the version from my git fork which has a fix for a non-writable
config directory if the config file already exists.

Dockerfile

@@ -8,7 +8,7 @@ RUN pip install --no-cache-dir pipenv
 WORKDIR /poquita
 COPY Pipfile* ./
 # hadolint ignore=DL3018
-RUN apk add --update --no-cache --virtual .lxml-build build-base libxslt-dev && \
+RUN apk add --update --no-cache --virtual .lxml-build build-base git libxslt-dev && \
     pipenv install --deploy --system && \
     apk del .lxml-build && \
     apk add --update --no-cache --virtual .lxml-runtime libxml2 libxslt

Pipfile

@@ -8,7 +8,7 @@ pre-commit = "*"
 docker-compose = "*"
 
 [packages]
-poca = "*"
+poca = {git = "https://github.com/adarnimrod/poca",ref = "non-writable-config-dir"}
 
 [requires]
 python_version = "3.6"