CI: fixup tr command

Author: NickCrews

justfile

@@ -23,7 +23,7 @@ test *FILES:
     #!/usr/bin/env bash
     # In windows github actions, the uname command returns "MSYS_NT-10.0-20348"
     # Search for "MSYS_NT"
-    if [ "$(uname | tr '[:upper:] [:lower:]' | grep 'msys_nt')" ]; then
+    if [ "$(uname | tr '[:upper:]' '[:lower:]' | grep 'msys_nt')" ]; then
         uv run --group test --all-extras pytest {{FILES}}
     else
         uv run --group test --all-extras pytest --doctest-modules {{FILES}}