Update README.md

Q1CHENL · web-flow · commit 1531530a6cad · 2024-03-29T01:29:03.000+08:00
diff --git a/README.md b/README.md
@@ -11,6 +11,7 @@ An interactive and intuitive todo TUI
 
 - Install: `pip install todoism`
 - Run: `todoism` or `todo`
+- Update: `pip install todoism --upgrade`
 
 ```
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