pre-commit: Add git.

Missing from the image after changing the base image.

images/pre-commit/Dockerfile

@@ -5,6 +5,7 @@ SHELL ["/bin/bash", "-o", "pipefail", "-c"]
 RUN apt-get update && \
     DEBIAN_FRONTEND=noninteractive apt-get install -y --no-install-recommends \
         docker.io \
+        git \
         python3-dev \
         python3-pip \
         python3-setuptools \