build(linstor): pin the upstream tag in the piraeus-operator make update target #5293

The piraeus-operator chart can be vendored at a version that does not match the LINSTOR images this repository builds. make update in packages/system/piraeus-operator takes whichever tag sorts last in git ls-remote --tags of piraeusdatastore/piraeus-operator, with no way to choose another one.

Today that tag is v2.12.1, which defaults LINSTOR CSI to v1.13.2. This repository builds CSI v1.11.2 and LINSTOR 1.33.3, pinned in packages/system/linstor/Makefile.

The same happens inside the 2.10 line. v2.10.8 already defaults CSI and the NFS server to v1.11.3, so the newest 2.10 tag changes the image set as well. To get a specific tag you have to edit the target locally and run it, and the resulting diff does not say which tag produced it.

I suggest taking the tag from a variable or a minor-line filter, as packages/system/kubeovn/Makefile does with grep '^v1\.15\.', and bumping it together with the LINSTOR and CSI versions.