ci: Replace travis with GitHub actions

.github/workflows/nightly.yml

@@ -0,0 +1,30 @@
+name: Rust Nightly
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  check:
+    name: Check
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions-rs/toolchain@v1
+      with:
+        toolchain: nightly
+        profile: minimal
+        override: true
+        components: rustfmt, clippy
+    - name: Check formatting
+      uses: actions-rs/cargo@v1
+      with:
+        command: fmt
+        args: -- --check
+    - name: Catch common mistakes
+      uses: actions-rs/cargo@v1
+      with:
+        command: clippy
+        args: --all-features --all-targets -- -D warnings

.github/workflows/stable.yml

@@ -0,0 +1,28 @@
+name: Rust Stable
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  check:
+    name: Check
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - uses: actions-rs/toolchain@v1
+      with:
+        toolchain: stable
+        profile: minimal
+        override: true
+    - name: Run tests
+      uses: actions-rs/cargo@v1
+      with:
+        command: test
+    - name: Run tests (unstable-pre-spec)
+      uses: actions-rs/cargo@v1
+      with:
+        command: test
+        args: --features unstable-pre-spec

.travis.yml

@@ -1,7 +0,0 @@
-language: rust
-sudo: false
-rust:
-  - stable
-  - nightly
-script:
-  - cargo test --features unstable-pre-spec