chore: adds linting fixes from KICS

Signed-off-by: Jennifer Power <[email protected]>

Dockerfile

@@ -1,11 +1,11 @@
+# kics-scan disable=fd54f200-402c-4333-a5a4-36ef6709af2f,b03a748a-542d-44f4-bb86-9199ab4fd2d5
 FROM python:3.8.1-slim as python-base
 
 ENV PYTHONUNBUFFERED=1 \
     # prevents python creating .pyc files
     PYTHONDONTWRITEBYTECODE=1 \
     \
     # pip
-    PIP_NO_CACHE_DIR=off \
     PIP_DISABLE_PIP_VERSION_CHECK=on \
     PIP_DEFAULT_TIMEOUT=100 \
     \
@@ -36,8 +36,8 @@ RUN apt-get update \
         build-essential
 
 # install poetry - respects $POETRY_VERSION & $POETRY_HOME
-RUN  python3.8 -m pip install --upgrade pip \
-     && pip install poetry=="$POETRY_VERSION"
+RUN  python3.8 -m pip install --no-cache-dir --upgrade pip \
+     && pip install --no-cache-dir poetry=="$POETRY_VERSION"
 
 # Cache runtime deps
 WORKDIR $PYSETUP_PATH
@@ -51,7 +51,9 @@ FROM python-base as final
 COPY --from=dependencies $PYSETUP_PATH $PYSETUP_PATH
 
 RUN apt-get update \
-    && apt-get install --no-install-recommends -y git
+    && apt-get install --no-install-recommends -y git \
+    && apt-get clean \
+    && rm -rf /var/lib/apt/lists/*
 
 ENTRYPOINT [ "/bin/sh", "-c", "python3.8 -m trestlebot \
            --markdown-path=${MARKDOWN_PATH} \