CI: install cargo-leptos via cargo-binstall instead of building from source

Building cargo-leptos from source pulls in swc/lightningcss/rhai and was
OOM-killing the aarch64 (Raspberry Pi) runner. cargo-leptos publishes
prebuilt aarch64-unknown-linux-gnu binaries, so binstall sidesteps the
compile entirely.

.gitea/workflows/release.yml

@@ -36,8 +36,15 @@ jobs:
             ~/.cargo/bin
           key: ${{ runner.os }}-${{ matrix.arch }}-cargo-leptos-${{ hashFiles('Cargo.lock') }}
 
+      - name: Install cargo-binstall
+        run: |
+          command -v cargo-binstall || \
+            curl -L --proto '=https' --tlsv1.2 -sSf \
+              https://raw.githubusercontent.com/cargo-bins/cargo-binstall/main/install-from-binstall-release.sh \
+              | bash
+
       - name: Install cargo-leptos
-        run: command -v cargo-leptos || cargo install cargo-leptos --locked
+        run: command -v cargo-leptos || cargo binstall cargo-leptos --locked --no-confirm
 
       - name: Build
         run: cargo leptos build --release