Update Rust version (#588)

Temporarily disables rustfmt example due to rust compiler error see #594

Dockerfile

@@ -63,7 +63,10 @@ RUN chmod a+rwx ${RUSTUP_DIR}
 
 # Install Rust toolchain.
 # We currently need the nightly version in order to be able to compile some of the examples.
-ARG RUST_VERSION=nightly-2019-07-18
+# See https://rust-lang.github.io/rustup-components-history/ for how to pick a version that supports
+# the appropriate set of components.
+# Make sure to update WORKSPACE too, e.g. when updating nightly version
+ARG RUST_VERSION=nightly-2020-02-06
 RUN rustup toolchain install ${RUST_VERSION}
 RUN rustup default ${RUST_VERSION}
 

WORKSPACE

@@ -251,11 +251,12 @@ http_archive(
 
 load("@io_bazel_rules_rust//rust:repositories.bzl", "rust_repository_set")
 
+# Make sure to update Dockerfile too, e.g. when updating nightly version
 rust_repository_set(
     name = "rust_linux_x86_64",
     exec_triple = "x86_64-unknown-linux-gnu",
     extra_target_triples = [],
-    iso_date = "2019-11-06",
+    iso_date = "2020-02-06",
     version = "nightly",
 )