Add OS maintenance strategy to documentation

Suggestion

Extend the CONTRIBUTING document to describe the strategy for including and adding new images, either by adding text or referring to a separate new document.

This should reference:

• which operating systems are included (currently Alpine and Debian)
• how / when new operating system versions are added
• how / when operating system versions are removed
• how the default operating system version is set and maintained for a given Node.js release line
• how the default Node.js version is set and maintained for a given operating system selection
• how architectures will be added / maintained / removed
• if supported architectures change during the lifecycle of Node.js / operating system versions, describe how these will be handled

Related

https://github.com/nodejs/docker-node/issues/2363

Inizia leggendo CONTRIBUTING.md e la discussione nella issue correlata 2363, quindi esamina come le immagini e le architetture Alpine e Debian attuali sono rappresentate nel repository. Il lavoro è completato quando la documentazione spiega il ciclo di vita dell’inclusione, delle versioni e delle architetture, i valori predefiniti e come vengono gestite le modifiche durante i cicli di vita di Node.js o del sistema operativo.