fix(dockerfile): bump python 3.8

Author: nold

Dockerfile

@@ -1,15 +1,14 @@
-FROM python:3.7-slim-stretch
+FROM python:3.8-slim
 
 RUN apt-get update && \
 	apt-get install --no-install-recommends -y \
-			git build-essential \
-			libssl-dev zlib1g-dev libbz2-dev libreadline-dev \
-			libsqlite3-dev libffi-dev libxml2-dev libxslt1-dev \
-			libre2-dev pkg-config && \
+      git wget ca-certificates git build-essential libssl-dev zlib1g-dev \
+      libbz2-dev libreadline-dev libsqlite3-dev libffi-dev libxml2-dev \
+      libxslt1-dev libre2-dev pkg-config && \
     pip3 install --no-binary lxml --upgrade git+https://github.com/ArchiveTeam/grab-site && \
     apt-get purge -y \
 			git build-essential pkg-config && \ 
-	apt-get autoremove -y && apt-get clean && \
+    apt-get autoremove -y && apt-get clean && \
     rm -rf /var/lib/apt/lists/* /var/tmp/* /tmp/*
 
 VOLUME /data