Start using GitHub Actions instead of Travis CI

Somewhat quick and dirty conversion, but seems to work fine. Certainly
better than nothing, since Travis CI does not run at all any longer.

.github/workflows/CI.yml

@@ -0,0 +1,49 @@
+name: CI
+
+on:
+  workflow_dispatch:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  build-and-test:
+    name: Build and test
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        submodules: true
+    - name: Build
+      run: |
+        cargo build
+    - name: Run tests
+      run: |
+        cargo test --features metadata
+    - name: Run tests with fancy
+      run: |
+        # Run these tests in release mode since they're slow as heck otherwise
+        cargo test --features default-fancy --no-default-features --release
+    - name: make stuff
+      run: |
+        make assets
+        make syntest
+        make syntest-fancy
+        rm -Rf examples
+    - name: Docs
+      run: |
+        # Only run doc build on stable until this is fixed: https://github.com/rust-lang/rust/issues/51661
+        cargo doc
+    - name: Run tests without default features
+      run: |
+        # default features are required for examples to build - so remove them from sight.
+        # Doc-tests may also use default features
+        rm -Rf examples && cargo test --lib --no-default-features
+    - name: Run Xi tests
+      run: |
+        # Test the build configuration that Xi uses
+        cargo test --lib --no-default-features --features "assets dump-load-rs"

Readme.md

@@ -3,7 +3,7 @@
 [![Crates.io](https://img.shields.io/crates/v/syntect.svg?maxAge=2591000)](https://crates.io/crates/syntect)
 [![Documentation](https://docs.rs/syntect/badge.svg)](https://docs.rs/syntect)
 [![Crates.io](https://img.shields.io/crates/l/syntect.svg?maxAge=2591000)]()
-[![Build Status](https://travis-ci.org/trishume/syntect.svg?branch=master)](https://travis-ci.org/trishume/syntect)
+[![Build Status](https://github.com/trishume/syntect/actions/workflows/CI.yml/badge.svg)](https://github.com/trishume/syntect/actions)
 [![codecov](https://codecov.io/gh/trishume/syntect/branch/master/graph/badge.svg)](https://codecov.io/gh/trishume/syntect)
 
 `syntect` is a syntax highlighting library for Rust that uses [Sublime Text syntax definitions](http://www.sublimetext.com/docs/3/syntax.html#include-syntax).