ci: Try speeding up CI again by enabling uv cache

.github/workflows/docs.yml

@@ -14,18 +14,20 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Python
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v5
         with:
           python-version: '3.x'
 
-      - uses: actions/cache@v3
-        name: Cache/restore pip data
+      - name: Setup uv
+        uses: astral-sh/setup-uv@v3
         with:
-          path: ~/.cache/pip
-          key: pip
+          enable-cache: true
+          # Just to give a glob.
+          # Lets us invalidate the cache with dummy changes to this file.
+          cache-dependency-glob: requirements.txt
 
       - name: Install Python dependencies
-        run: pip install -r requirements.txt
+        run: uv venv && uv pip install -r requirements.txt
 
       - name: Cache/restore Playwright browsers
         uses: actions/cache@v3
@@ -37,7 +39,7 @@ jobs:
         run: shot-scraper install
 
       - name: Build everything
-        run: python build.py
+        run: .venv/bin/python build.py
 
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v2

build.py

@@ -118,7 +118,7 @@ def install_deps(theme: Theme) -> None:
         check=True,
         stdout=subprocess.DEVNULL,
         stderr=subprocess.DEVNULL,
-        env={"VIRTUAL_ENV": str(venv_dir)},
+        env={"VIRTUAL_ENV": str(venv_dir), "UV_PROJECT_ENVIRONMENT": str(venv_dir)},
     )