chore: change runner workdir

docs/developer/cicd_runner.md

@@ -42,7 +42,7 @@ tar -xf node-v20.11.1-linux-x64.tar.xz --strip-components=2 -C ~/.local/bin/ nod
 rm node-v20.11.1-linux-x64.tar.xz
 ```
 
-Change the location of the cache:
+Change the location of the working directory (uv .venvs are built here, take up lots of space)
 
 ```
 mkdir -p /sls/bd/hla/.cache/act
@@ -51,9 +51,10 @@ mkdir -p /sls/bd/hla/.cache/act
 and edit `/etc/act_runner/config.yaml`
 
 ```
-cache:
-  enabled: true
-  dir: "/sls/bd/hla/.cache/act"
+host:
+  # The parent directory of a job's working directory.
+  # If it's empty, $HOME/.cache/act/ will be used.
+  workdir_parent: "/sls/bd/hla/.cache/act"
 ```
 
 ## Manually run the runner