gh: add runner versioning policy, fix #32

README.md

@@ -20,3 +20,4 @@ organization are also stored here.
   assignments, PR discussions, issue closure, and documentation.
 - [Contributing](CONTRIBUTING.md) - We welcome contributions! Please take a 
   look if you have suggestions, corrections, or documents to add. 
+- [GitHub](gh.md) - GitHub-specific development practices and policies.

gh.md

@@ -0,0 +1,16 @@
+# GitHub
+
+## Action runners
+We use standard GitHub-hosted runners for CI/CD jobs. Most of our tasks use
+Ubuntu-based runners and they should be preferred when action doesn't require
+some specific OS/hardware platform. Since in general runners are limited
+hardware-wise actions should use the minimal required version of the runner.
+As of Dec 2025 this means using ubuntu-slim if possible for the task.
+
+Using "latest" version of runner (and OS respectively) is preferred unless
+there are valid reasons to pick any particular one. Usually "latest" is
+the most widely available version and actions can't get obsolete because of
+missing runners this way and we get more uniformity between different
+system components. While theoretically it can bring some instability because
+of OS updates practically it's rarely a problem and even some problem happens
+we better know it sooner than later.