v0.17.0

• Reverted to static linking by default as we had prior to 0.16.0. You can still get dynamic linking
  by setting :allow_static_linking 0 which is recommended if it works for you. Forcing dynamic
  linking was breaking in hard-to-debug ways for several people on both Mac and Linux.
• Fixes for async-await support.
• Added commands to set runtime environment variables (:env) and build environment variables
  (:build_env).
• An evcxr.toml in your startup directory can now be used to override your target-dir. Thanks
  baiguoname.
• Added support for selecting rustc's codegen backend. You can now use the cranelift backend by
  doing :toolchain nightly then :codegen_backend cranelift.
• Updated rust-analyzer
• Minimum rust version is now 1.74 due to changes in rust-analyzer