Update URIs following initial push

I changed the name of the repository in gitea so the URIs in the README,
dune-project, and partridge.opam files need updating.

README.md

@@ -1,4 +1,4 @@
-# Triangle Square Cubes
+# Partridge
 
 Following Matt Parker's Video on Squares of Triangle Numbers being sum of cubes,
 and the Partridge Problem: https://youtu.be/eqyuQZHfNPQ?si=hbOQdVKBC-jwvysk.
@@ -12,13 +12,15 @@ Apache-2.0 license.
 
 ## Running the code
 
-### Initial setup
+### Prerequisites
 
 Prerequisite is to have `git` and `opam` installed on the path.
 
+### Code checkout and setup.
+
 ```sh
-git clone ...
-cd triangle-square-cubes
+git clone https://gitea.gretton-dann.org.uk/mgrettondann/partridge.git
+cd partridge
 opam switch create .
 opam update
 opam install . --deps-only