docs(README): simplify install without prereleases

Author: tony

README.md

@@ -44,23 +44,17 @@ Stable release:
 pip install libtmux
 ```
 
-Pre-releases (alpha / beta / rc):
+With pipx:
 
 ```bash
-pip install --upgrade --pre libtmux
-```
-
-With pipx (installs as `libtmux@next`):
-
-```bash
-pipx install --suffix=@next "libtmux" --pip-args "\--pre" --force
+pipx install libtmux
 ```
 
 With uv / uvx:
 
 ```bash
-uv add libtmux --prerelease allow
-uvx --from "libtmux" --prerelease allow python
+uv add libtmux
+uvx --from "libtmux" python
 ```
 
 From the main branch (bleeding edge):