Upgrade rust stable to 1.29

ci/buildkite.yml

@@ -1,5 +1,5 @@
 steps:
-  - command: "ci/docker-run.sh solanalabs/rust:1.28.0 ci/test-stable.sh"
+  - command: "ci/docker-run.sh solanalabs/rust:1.29.0 ci/test-stable.sh"
     name: "stable [public]"
     env:
       CARGO_TARGET_CACHE_NAME: "stable"

ci/docker-rust/Dockerfile

@@ -1,6 +1,6 @@
 # Note: when the rust version (1.28) is changed also modify
 # ci/buildkite.yml to pick up the new image tag
-FROM rust:1.28
+FROM rust:1.29.0
 
 RUN set -x && \
     apt update && \

ci/version-check.sh

@@ -23,8 +23,8 @@ nightly)
   require cargo 1.29.[0-9]+-nightly
   ;;
 stable)
-  require rustc 1.28.[0-9]+
-  require cargo 1.28.[0-9]+
+  require rustc 1.29.[0-9]+
+  require cargo 1.29.[0-9]+
   ;;
 *)
   echo Error: unknown argument: "$1"