ci: pin uv for 3.7 support

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

Author: henryiii

.github/workflows/build.yml

@@ -132,6 +132,7 @@ jobs:
       - uses: astral-sh/setup-uv@v6
         with:
           enable-cache: false
+          version: "0.7.12"
 
       - name: Setup environment
         run: |