Create post-refresh hook for all plugins with script

tools/generate_dnsplugins_postrefreshhook.sh

@@ -0,0 +1,36 @@
+#!/bin/bash
+# Generate the hooks/post-refresh file for all DNS plugins
+set -e
+
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+CERTBOT_DIR="$(dirname "${DIR}")"
+
+for PLUGIN_PATH in "${CERTBOT_DIR}"/certbot-dns-*; do
+  PLUGIN=$(basename "${PLUGIN_PATH}")
+  mkdir -p "${PLUGIN_PATH}/snap/hooks"
+  cat <<EOF > "${PLUGIN_PATH}/snap/hooks/post-refresh"
+# This file is generated by tools/generate_dnsplugins_postrefreshhook.sh and should not be edited manually.
+#!/bin/sh -e
+
+# get certbot version
+if [ ! -f "\$SNAP/certbot-shared/certbot-version.txt" ]; then
+  echo "No certbot version available; not doing version comparison check" >> "\$SNAP_DATA/debuglog"
+  exit 0
+fi
+cb_installed=\$(cat \$SNAP/certbot-shared/certbot-version.txt)
+
+# get required certbot version for plugin. certbot version must be at least the plugin's
+# version. note that this is not the required version in setup.py, but the version number itself.
+cb_required=\$(grep -oP "version = '\K.*(?=')" \$SNAP/setup.py)
+
+
+python3 -c "import sys; from setuptools._vendor.packaging import version; sys.exit(1) if\
+  version.parse('\$cb_installed') < version.parse('\$cb_required') else sys.exit(0)" || exit_code=\$?
+if [ "\$exit_code" -eq 1 ]; then
+  echo "Certbot is version \$cb_installed but needs to be at least \$cb_required before" \
+    "this plugin can be updated; will try again on next refresh."
+  exit 1
+fi
+
+EOF
+done