Add checksum and checksum check

Author: Morl99

Dockerfile

@@ -2,10 +2,12 @@ ARG POSTGRESQL_VERSION="13"
 FROM bitnami/postgresql:$POSTGRESQL_VERSION
 LABEL org.opencontainers.image.source="https://github.com/dbsystel/postgresql-partman-container"
 ARG PARTMAN_VERSION="v4.7.3"
+ARG PARTMAN_CHECKSUM="c0db6784e2d337645d8a1a89eb947635e547eab2be24545ebc52f02ee98098648cc00ae86adf677b196023e9290522a30b87b02081f782bfc8de4bd30c39980c"
 USER root
 RUN install_packages wget gcc make build-essential
 RUN cd /tmp \
     && wget "https://github.com/pgpartman/pg_partman/archive/refs/tags/${PARTMAN_VERSION}.tar.gz" \
+    && echo "${PARTMAN_CHECKSUM} ${PARTMAN_VERSION}.tar.gz" | sha512sum --check \
     && export C_INCLUDE_PATH=/opt/bitnami/postgresql/include/:/opt/bitnami/common/include/ \
     && export LIBRARY_PATH=/opt/bitnami/postgresql/lib/:/opt/bitnami/common/lib/ \
     && export LD_LIBRARY_PATH=/opt/bitnami/postgresql/lib/:/opt/bitnami/common/lib/ \