Allow to specify package version

**Is your feature request related to a problem? Please describe.**
My customers are not able to specify a version. This is problematic as they roll patches out to lower environments first, and sometimes (often times) by the time they get to prod, the version pushed by this agent will be different than what was tested in lower environments.

**Describe the solution you'd like**
Allow the customer to specify an image version. In zypper, you can do:
zypper install =
But the extension doesn't expose the version:
# Install update
self.single_package_upgrade_cmd = 'sudo zypper --non-interactive update '
self.zypper_install_security_patches = 'sudo zypper --non-interactive patch --category security'

**Describe alternatives you've considered**
The customer is working to accelerate their patching cycle, but no workaround exists with the extension itself that I am aware of.

Start by locating where the extension defines and invokes the shown zypper update and security-patch commands. Trace how package selections are supplied, then define how a customer-provided version reaches the command and verify that the resulting installation pins the requested version.

Scritto dal modello di indicizzazione a partire dal testo della issue.