Change docker builds to include specific version of Rust (1.35.0)
diff --git a/build/docker/ubuntu-bionic/Dockerfile b/build/docker/ubuntu-bionic/Dockerfile
index c8131bb..b508b1e 100644
--- a/build/docker/ubuntu-bionic/Dockerfile
+++ b/build/docker/ubuntu-bionic/Dockerfile
@@ -257,7 +257,7 @@
ruby-bundler
# Rust dependencies
-RUN curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain stable -y
+RUN curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain 1.35.0 -y
# Swift on Linux for cross tests
RUN cd / && \