CI: use rustup instead of system Rust packages

blazesym's dependency indexmap v2.12.0 requires Rust 1.82+, but Ubuntu
22.04's apt packages only provide Rust 1.75.0. Switch to installing Rust
via rustup to get a recent stable version.

Signed-off-by: Andrii Nakryiko <[email protected]>

Author: anakryiko

.github/docker/Dockerfile.ubuntu

@@ -38,8 +38,11 @@ RUN apt-get update && apt-get install -y \
       llvm-${LLVM_VERSION}-runtime \
       libllvm${LLVM_VERSION} \
       make cmake pkg-config \
-      rustc cargo rustfmt \
       sudo \
       && apt-get -y clean
 
+# Install Rust via rustup to get a recent version (required for blazesym dependencies)
+RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain stable --component rustfmt
+ENV PATH="/root/.cargo/bin:${PATH}"
+
 RUN ln -s /usr/bin/clang-${LLVM_VERSION} /usr/bin/clang && ln -s /usr/bin/llvm-strip-${LLVM_VERSION} /usr/bin/llvm-strip