Update .devcontainer/Dockerfile

Co-authored-by: Dan Chiarlone <danilochiarlone@gmail.com>
Signed-off-by: Simon Davies <simongdavies@users.noreply.github.com>

Author: simongdavies

.devcontainer/Dockerfile

@@ -59,6 +59,6 @@ RUN curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y \
     && rustup target add x86_64-unknown-linux-gnu \
     && rustup target add x86_64-unknown-none      \
     && rustup target add x86_64-pc-windows-msvc   \
-    && rustup toolchain add  nightly-x86_64-unknown-linux-gnu \
+    && rustup toolchain add nightly-x86_64-unknown-linux-gnu \
     && cargo install just