Don't install tree on CI

The `tree` package provides the `tree` command, which is useful but
does not currently appear to be used anywhere.

Author: EliahKagan

.github/workflows/ci.yml

@@ -65,7 +65,7 @@ jobs:
       - uses: dtolnay/rust-toolchain@stable
       - uses: Swatinem/rust-cache@v2
       - name: Setup dependencies
-        run: sudo apt-get install -y --no-install-recommends liblzma-dev tree
+        run: sudo apt-get install -y --no-install-recommends liblzma-dev
       - uses: extractions/setup-just@v2
       - uses: taiki-e/install-action@v2
         with:
@@ -91,8 +91,8 @@ jobs:
       - uses: Swatinem/rust-cache@v2
       - name: Setup dependencies (macos)
         if: startsWith(matrix.os, 'macos')
-        run: brew install tree openssl gnu-sed
-      - name: "cargo check default features"
+        run: brew install openssl gnu-sed
+      - name: cargo check default features
         if: startsWith(matrix.os, 'windows')
         run: cargo check --workspace --bins --examples
       - uses: taiki-e/install-action@v2