replace travis with GH actions (#367)

.github/workflows/ci.yml

@@ -0,0 +1,31 @@
+name: CI
+
+on: [push]
+
+jobs:
+  ci:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [10.x, 12.x, 14.x]
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v2
+      with:
+        node-version: ${{ matrix.node }}
+
+    - name: Install dependencies
+      run: npm i
+
+    - name: Lint, test, and build
+      run: npm start validate
+
+    - name: Check test coverage
+      uses: codecov/codecov-action@v1
+      with:
+        token: ${{ secrets.CODECOV_TOKEN }} # not required for public repos
+

.github/workflows/release.yml

@@ -0,0 +1,29 @@
+name: Release
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
+
+    - uses: actions/setup-node@v2
+      with:
+        node-version: '12.x'
+
+    - run: npm i
+
+    - run: npm start build
+
+    - name: Release
+      env:
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        NPM_TOKEN: ${{ secrets.NPM_TOKEN }}
+      run: npx semantic-release@15

.github/workflows/stale.yml

@@ -0,0 +1,19 @@
+name: Mark stale issues and pull requests
+
+on:
+  schedule:
+  - cron: "0 0 * * *"
+
+jobs:
+  stale:
+
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/stale@v1
+      with:
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        stale-issue-message: 'Stale issue'
+        stale-pr-message: 'Stale pull request'
+        stale-issue-label: 'no-issue-activity'
+        stale-pr-label: 'no-pr-activity'