doc: update `pipx` related links to the latest

CONTRIBUTING.md

@@ -185,7 +185,7 @@ If you are helping with the triage of reported issues, this section provides som
 
 #### Multiple versions
 
-Often times you would want to attempt to reproduce issues with multiple versions of `poetry` at the same time. For these use cases, the [pipx project](https://pipxproject.github.io/pipx/) is useful.
+Often times you would want to attempt to reproduce issues with multiple versions of `poetry` at the same time. For these use cases, the [pipx project](https://pypa.github.io/pipx/) is useful.
 
 You can set your environment up like so.
 

docs/_index.md

@@ -155,7 +155,7 @@ curl -sSL https://install.python-poetry.org | POETRY_UNINSTALL=1 python3 -
 
 {{< tab tabID="installing-with-pipx" >}}
 
-Using [`pipx`](https://github.com/pipxproject/pipx) to install Poetry is also possible.
+Using [`pipx`](https://github.com/pypa/pipx) to install Poetry is also possible.
 
 `pipx` is used to install Python CLI applications globally while still isolating them in virtual environments.
 This allows for clean upgrades and uninstalls.

docs/contributing.md

@@ -205,7 +205,7 @@ If you are helping with the triage of reported issues, this section provides som
 
 #### Multiple versions
 
-Often times you would want to attempt to reproduce issues with multiple versions of `poetry` at the same time. For these use cases, the [pipx project](https://pipxproject.github.io/pipx/) is useful.
+Often times you would want to attempt to reproduce issues with multiple versions of `poetry` at the same time. For these use cases, the [pipx project](https://pypa.github.io/pipx/) is useful.
 
 You can set your environment up like so.