wren node: install hints and docs pin the public v2.0.0 tag

backend/fluksio/flow/nodes/wren.py

@@ -36,12 +36,12 @@ def _wren() -> Any:
         # Not `pip install wren`: that name on PyPI is another package.
         raise RuntimeError(
             "the wren node needs the model: pip install "
-            "git+https://github.com/stroblme/wren"
+            "git+https://github.com/stroblme/wren@v2.0.0"
         ) from None
     if not hasattr(wren, "Target"):
         raise RuntimeError(
             "the wren node needs wren 2, the installed one is older: pip install "
-            "--upgrade git+https://github.com/stroblme/wren"
+            "--upgrade git+https://github.com/stroblme/wren@v2.0.0"
         )
     return wren
 

docs/reference/node-types.md

@@ -345,7 +345,7 @@ use a [batch flow](../concepts/runs.md) and a Function node.
 [Wren](https://github.com/stroblme/wren) is an optional local language model
 that turns short commands into calls on a fixed list of targets. Install it in
 the engine's environment with
-`pip install git+https://github.com/stroblme/wren`. The `wren` package on PyPI
+`pip install git+https://github.com/stroblme/wren@v2.0.0`. The `wren` package on PyPI
 is an unrelated one. Without the model the node reports a missing dependency.
 [Wren's own docs](https://stroblme.github.io/wren/) explain how to describe
 targets, train a model for them, and what a model can and cannot do.
@@ -452,7 +452,7 @@ the draft, and publishing puts it live. `POST` and `GET` on
 
 Training needs wren's `train` extra, which brings JAX, where the run executes:
 in **Modules** (see [Packages](../code/nodes.md#packages)) or on a worker. List
-`wren[train] @ https://github.com/stroblme/wren/archive/main.tar.gz` there
+`wren[train] @ https://github.com/stroblme/wren/archive/refs/tags/v2.0.0.tar.gz` there
 (an archive, since the engine image has no git). The flow comes from
 wren and is registered once with `fluksio sync wren.flow`, run from an
 environment with `wren[train]` and fluksio. Until then Train answers that the