ci: install Rust via rustup installer script

The act-runner environment does not have rustup pre-installed.
Install it using the official sh.rustup.rs script and append
~/.cargo/bin to GITHUB_PATH so subsequent steps can find the tools.

Node.js-based actions (actions/checkout, gitea-release-action) run
on the host runner where Node.js is available, so no container image
is needed.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.gitea/workflows/release.yml

@@ -11,7 +11,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Install Rust stable
-        run: rustup update stable && rustup default stable
+        run: |
+          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain stable
+          echo "$HOME/.cargo/bin" >> "$GITHUB_PATH"
       - name: Add musl target
         run: rustup target add x86_64-unknown-linux-musl
       - name: Install musl tools
@@ -36,7 +38,9 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Install Rust stable
-        run: rustup update stable && rustup default stable
+        run: |
+          curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain stable
+          echo "$HOME/.cargo/bin" >> "$GITHUB_PATH"
       - name: Install cross
         run: cargo install cross --locked
       - name: Build