Auto merge of #1587 - lzutao:only-gha, r=RalfJung

build: Gate only on GHA: remove travis and appveyor ci config

It's been over a week since #1571 merged.
The GHA evaluation is successful.

This PR removes CI config of travis and appveyor.
Now MIRI gates on github actions CI only.

Will need <https://github.com/rust-lang/homu/pull/109> to merge first,
otherwise bors will stuck.

Also, one may need to remove `continuous-integration/appveyor/pr` CI checks
in repo settings or appeveyor website.

.appveyor.yml

@@ -1,50 +0,0 @@
-build: off # No Visual Studio auto-build.
-environment:
-  global:
-    PROJECT_NAME: miri
-  matrix:
-    - HOST_TARGET: i686-pc-windows-msvc
-matrix:
-  fast_finish: true # Immediately finish build once one of the jobs fails.
-cache:
-- '%USERPROFILE%\.cargo'
-- '%USERPROFILE%\.rustup'
-
-# branches to build
-branches:
-  # whitelist
-  only:
-  - auto
-  - try
-
-install:
-# Compute the Rust version we use.
-- set /p RUSTC_HASH=<rust-version
-# Install Rust. We use the "stable" toolchain for better caching, it is just used to build `rustup-toolchain-install-master`.
-# But we also need to take into account that the build cache might have a different, outdated default.
-- curl -sSf --retry 3 -o rustup-init.exe https://win.rustup.rs/
-- rustup-init.exe -y --default-host %HOST_TARGET% --default-toolchain none --profile minimal
-- set PATH=%USERPROFILE%\.cargo\bin;%PATH%
-- rustup default stable
-- rustup toolchain uninstall beta nightly
-- rustup update
-# Install "master" toolchain.
-- cargo install rustup-toolchain-install-master
-- rustup-toolchain-install-master -f -n master %RUSTC_HASH% -c rust-src -c rustc-dev -c llvm-tools
-- rustup default master
-- rustc --version
-- cargo --version
-
-test_script:
-# Add python3 path: https://www.appveyor.com/docs/windows-images-software/#python
-- set PATH=C:\Python35-x64;%PATH%
-- bash ci.sh
-
-after_test:
-# Don't cache "master" toolchain, it's a waste.
-- rustup default stable
-- rustup toolchain uninstall master
-
-notifications:
-- provider: Email
-  on_build_success: false

.travis.yml

@@ -1,60 +0,0 @@
-language: generic
-jobs:
-  include:
-  - os: linux
-    env: HOST_TARGET=x86_64-unknown-linux-gnu
-  - os: osx
-    env: HOST_TARGET=x86_64-apple-darwin
-dist: xenial
-cache:
-  # Cache the global cargo directory, but NOT the local `target` directory which
-  # we cannot reuse anyway when the nightly changes (and it grows quite large
-  # over time).
-  directories:
-  - $HOME/.cargo
-  - $HOME/.rustup
-
-# Run in PRs and for bors, but not on master.
-branches:
-  only:
-  - master
-  - auto
-  - try
-if: branch = auto OR branch = try OR type = pull_request OR type = cron
-
-before_script:
-# Compute the Rust version we use. We do not use "language: rust" to have more control here.
-- |
-  if [[ "$TRAVIS_EVENT_TYPE" == cron ]]; then
-    RUSTC_HASH=$(git ls-remote https://github.com/rust-lang/rust.git master | awk '{print $1}')
-  else
-    RUSTC_HASH=$(cat rust-version)
-  fi
-# Install Rust. We use the "stable" toolchain for better caching, it is just used to build `rustup-toolchain-install-master`.
-# But we also need to take into account that the build cache might have a different, outdated default.
-- curl https://build.travis-ci.org/files/rustup-init.sh -sSf | sh -s -- -y --default-toolchain none --profile minimal
-- export PATH=$HOME/.cargo/bin:$PATH
-- rustup default stable
-- rustup toolchain uninstall beta nightly
-- rustup update
-# Install "master" toolchain.
-- cargo install rustup-toolchain-install-master
-- travis_retry rustup-toolchain-install-master -f -n master $RUSTC_HASH -c rust-src -c rustc-dev -c llvm-tools
-- rustup default master
-- rustc --version
-- cargo --version
-
-script:
-- ./ci.sh
-
-before_cache:
-# Don't cache "master" toolchain, it's a waste.
-- rustup default stable
-- rustup toolchain uninstall master
-
-notifications:
-  email:
-    on_success: never
-    recipients:
-    - post+travis@ralfj.de
-    - travis-miri@oli-obk.de