uv pip install -U will downgrade already-installed packages #10089
Description
If you uv init packaging, then change the version to 1000 and install it, then run uv pip install -U black, we'll actually downgrade packaging unnecessarily:
❯ uv pip install -U black
Resolved 6 packages in 93ms
Prepared 5 packages in 0.25ms
Uninstalled 1 package in 0.62ms
Installed 5 packages in 5ms
+ black==24.10.0
+ mypy-extensions==1.0.0
- packaging==1000 (from file:///Users/crmarsh/workspace/puffin/packaging)
+ packaging==24.2
+ pathspec==0.12.1
+ platformdirs==4.3.6