Build proxysql packages with version tagged docker image

[mirostauder]

docker images proxysql/packaging are being tagged with a version since v2.5.3 release
https://hub.docker.com/r/proxysql/packaging/tags?page=2&page_size=&ordering=&name=2.5.3

Currently (as of v2.6.3) for package building, an image without a version tag is used (the latest), this hurts reproducible builds and leads to issues when building other versions.

Make sure a ProxySQL packages are built with the correct proxysql/packaging image
add a variable IMGVER based on CURVER, to specify the version.

https://github.com/sysown/proxysql/blob/01d1fc9828a5da09896acd2287be48335bbc1ada/Makefile#L38C16-L39C1

e.g.

CURVER=2.6.3
IMGVER=2.6.3

will use proxysql/packaging images tagged with 2.6.3
https://hub.docker.com/r/proxysql/packaging/tags?page=2&page_size=&ordering=&name=2.6.3

[renecannao]

Thinking ...
It is even possible that different package images are updated at different times, for example we may need to update for a specific OS and not for other.
Maybe the tag should be on a per-distro basis, thus defined in the docker-compose file .

[mirostauder]

implemented in PR #4617