Set the RYE_HOME env var to fix error setting up shell completion

Fixing:

```
18.40 The rye directory /root/.rye/shims was not detected on PATH.
18.40 It is highly recommended that you add it.
18.40 Added to PATH.
18.40 note: for this to take effect you will need to restart your shell or run this manually:
18.40
18.40     source "$HOME/.rye/env"
18.40
18.40 To make it work with zsh, you might need to add this to your .zprofile:
18.40
18.40     source "$HOME/.rye/env"
18.40
18.40 For more information read https://rye.astral.sh/guide/installation/
18.40
18.40 All done!
18.41 Activating bash completion for 'rye'
18.41 ./install.sh: 14: rye: not found
18.41 ERROR: Feature "Rye" (ghcr.io/e-gineering/devcontainer-features/rye) failed to install
```

src/rye/devcontainer-feature.json

@@ -1,13 +1,14 @@
 {
     "name": "Rye",
-    "version": "1.2.0",
+    "version": "1.2.1",
     "id": "rye",
     "description": "A Hassle-Free Python Experience",
     "installsAfter": [
         "ghcr.io/devcontainers/features/python"
     ],
     "containerEnv": {
         "PATH": "/usr/local/lib/rye/shims:${PATH}",
+        "RYE_HOME": "/usr/local/lib/rye",
         "RYE_NO_AUTO_INSTALL": "1"
     },
     "postCreateCommand": "echo 'source \"$HOME/.rye/env\"' >> ~/.profile",