Now using uv instead of pipx

- Update the installation instructions in the readme.
- Change the install script to use uv.

packaging/make-readme.py

@@ -18,18 +18,28 @@ def main():
 
 ## Summary
 
-Eris maintains an up-to-date set of reports for every file in a codebase.
+Eris maintains an up to date set of reports for every file in a codebase.
 
 ## Installation
 
 #### Debian / Ubuntu / Fedora / Arch / Alpine
 
-Install eris with pipx, then install all the tools eris uses:
+Firstly uv is needed to install eris.
 
-    pipx install --system-site-packages git+https://gitlab.com/ahamilton/eris@v2025.06.04#subdirectory=eris
+To install uv:
+
+    curl -LsSf https://astral.sh/uv/install.sh | sh
+
+For other ways to install uv see its [installation page](https://docs.astral.sh/uv/getting-started/installation/).
+
+Then use uv to install eris:
+
+    uv tool install git+https://gitlab.com/ahamilton/eris@v2025.06.04
+
+Then use eris to install all the tools it uses:
     eris --install-all-tools
 
-Or install from source: (includes tools)
+Or install from source: (including tools)
 
     git clone https://gitlab.com/ahamilton/eris
     cd eris