Fix the docker build by updating rust (tgstation#40331)

* Fix the docker build by updating rust

* Use absolute cargo path

Dockerfile

@@ -14,9 +14,10 @@ WORKDIR /rust_g
 
 RUN apt-get install -y --no-install-recommends \
     libssl-dev \
-    rustc \
-    cargo \
     pkg-config \
+    curl \
+    gcc-multilib \
+    && curl https://sh.rustup.rs -sSf | sh -s -- -y --default-host i686-unknown-linux-gnu \
     && git init \
     && git remote add origin https://github.com/tgstation/rust-g
 
@@ -25,7 +26,7 @@ COPY dependencies.sh .
 RUN /bin/bash -c "source dependencies.sh \
     && git fetch --depth 1 origin \$RUST_G_VERSION" \
     && git checkout FETCH_HEAD \
-    && cargo build --release
+    && ~/.cargo/bin/cargo build --release
 
 FROM build_base as bsql