Add wget to the static analysis container

Required to support installing ejson (or whatever else) here, as in
https://github.com/springload/cookiecutter-wagtail/commit/0dd2497e061dae033e5e51f860953b9284ed0dc0

Author: haydngreatnews

Dockerfile

@@ -3,4 +3,7 @@ FROM python:3.9-slim AS static-analysis
 WORKDIR /project
 COPY requirements/static_analysis.txt requirements/static_analysis.txt
 RUN pip install -r requirements/static_analysis.txt
+RUN apt-get update && apt-get install -y \
+    wget \
+    && rm -rf /var/lib/apt/lists/*
 COPY . /project