update note

README.md

@@ -3,6 +3,18 @@
 
 ----
 
+How to update the basesystem:
+
+```
+git remote add ip7z https://github.com/ip7z/7zip.git
+git fetch ip7z --tags
+git checkout ip7z/main
+git checkout -B ip7z
+git push ___ ip7z --tags
+```
+
+----
+
 This repository's goal was these:
 
 - to provide automated p7zip binary generator for Windows / macOS (x86-64/arm64) / Linux / Android
@@ -14,8 +26,6 @@ I'd like to have these patch merged into jinfeihan57/p7zip, but I had issue in r
 
 Excuse: to utilize git's 3-way merge, I have suggested https://github.com/jinfeihan57/p7zip/issues/179 , but it was not adopted.
 
-This repo has been archived (might be temporary unarchived when I got interested but it will happen rarely).
-
 ----
 
 Refer https://github.com/cielavenir/p7zip/blob/main/.github/workflows/ci.yaml for building manually.