use GitHub Actions instead of Travis CI

.github/workflows/unit-tests.yml

@@ -0,0 +1,54 @@
+name: Unit tests
+
+on:
+  push:
+    branches: [ master ]
+    paths:
+      - '.github/workflows/*'
+      - 'src/**'
+      - 'Cargo.*'
+      - build.rs
+  pull_request:
+    branches: [ master ]
+    paths:
+      - '.github/workflows/*'
+      - 'src/**'
+      - 'Cargo.*'
+      - build.rs
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  unit-tests:
+    runs-on: ${{ matrix.os }}
+
+    continue-on-error: ${{ matrix.rust == 'nightly' }}
+
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+        rust: [1.48.0, stable, beta, nightly]
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Install Rust toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: ${{ matrix.rust }}
+          override: true
+
+      - name: Install cargo-hack
+        uses: actions-rs/cargo@v1
+        with:
+          command: install
+          args: cargo-hack
+
+      - name: Run unit tests
+        uses: actions-rs/cargo@v1
+        with:
+          command: hack
+          args: test --feature-powerset

.travis.yml

@@ -1,19 +0,0 @@
-language: rust
-rust:
-  - 1.45.2
-  - stable
-  - beta
-  - nightly
-
-jobs:
-  fast_finish: true
-  allow_failures:
-    - rust: nightly
-
-  include:
-    - name: 'Rust: test with all features'
-      rust: stable
-      install:
-        - cargo install cargo-hack
-      script:
-        - cargo hack test --feature-powerset