fix: set a fixed version of Barman to 3.12.1 (#68)

The latest released version of Barman 3.13.0 introduced a change
in the argment list for the restore.

For more information check the following issue:
cloudnative-pg/cloudnative-pg#6932

Signed-off-by: Jonathan Gonzalez V. <jonathan.gonzalez@enterprisedb.com>

Author: sxd

PostGIS/update.sh

@@ -51,7 +51,8 @@ fetch_postgres_image_version() {
 # Get the latest Barman version
 latest_barman_version=
 _raw_get_latest_barman_version() {
-	curl -s https://pypi.org/pypi/barman/json | jq -r '.releases | keys[]' | sort -Vr | head -n1
+#	curl -s https://pypi.org/pypi/barman/json | jq -r '.releases | keys[]' | sort -Vr | head -n1
+	echo "3.12.1"
 }
 get_latest_barman_version() {
 	if [ -z "$latest_barman_version" ]; then