Update Rust version to 1.39.0.

Dockerfile

@@ -1,4 +1,4 @@
-FROM circleci/rust:1.38.0-stretch as wasmer-build-env
+FROM circleci/rust:1.39.0-stretch as wasmer-build-env
 RUN sudo apt-get update && \
   sudo apt-get install -y --no-install-recommends \
   cmake \

README.md

@@ -181,7 +181,7 @@ nginx and Lua do not work on Windows - you can track the progress on [this issue
 
 ## Building
 
-[![Rustc Version 1.38+](https://img.shields.io/badge/rustc-1.37+-red.svg?style=flat-square)](https://blog.rust-lang.org/2019/09/26/Rust-1.38.0.html)
+[![Rustc Version 1.39+](https://img.shields.io/badge/rustc-1.39+-red.svg?style=flat-square)](https://blog.rust-lang.org/2019/09/26/Rust-1.39.0.html)
 
 Wasmer is built with [Cargo](https://crates.io/), the Rust package manager.
 

azure-pipelines.yml

@@ -22,7 +22,7 @@ jobs:
       - script: cargo fmt --all -- --check
         displayName: Lint
     variables:
-      rust_toolchain: '1.38.0'
+      rust_toolchain: '1.39.0'
 
   - job: Test
     strategy:
@@ -39,7 +39,7 @@ jobs:
           CARGO_HTTP_CHECK_REVOKE: false
         windows:
           imageName: "vs2017-win2016"
-          rust_toolchain: '1.38.0'
+          rust_toolchain: '1.39.0'
     pool:
       vmImage: $(imageName)
     condition: in(variables['Build.SourceBranch'], 'refs/heads/master', 'refs/heads/staging', 'refs/heads/trying')
@@ -100,7 +100,7 @@ jobs:
           MACOSX_DEPLOYMENT_TARGET: 10.10
         windows:
           imageName: "vs2017-win2016"
-          rust_toolchain: '1.38.0'
+          rust_toolchain: '1.39.0'
           # RUSTFLAGS: -Ctarget-feature=+crt-static
     pool:
       vmImage: $(imageName)
@@ -163,7 +163,7 @@ jobs:
           MACOSX_DEPLOYMENT_TARGET: 10.10
         windows:
           imageName: "vs2017-win2016"
-          rust_toolchain: '1.38.0'
+          rust_toolchain: '1.39.0'
           # RUSTFLAGS: -Ctarget-feature=+crt-static
     pool:
       vmImage: $(imageName)