Replace Travis CI with GitHub Actions build/lint/test workflows

.github/workflows/build.yml

@@ -0,0 +1,17 @@
+name: Build for production
+
+on: [push]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install dependencies
+        uses: borales/[email protected]
+        with:
+          cmd: install
+      - name: Run production build
+        uses: borales/[email protected]
+        with:
+          cmd: build

.github/workflows/lint.yml

@@ -0,0 +1,21 @@
+name: Lint code
+
+on: [push]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install dependencies
+        uses: borales/[email protected]
+        with:
+          cmd: install
+      - name: Lint JavaScript/Vue files
+        uses: borales/[email protected]
+        with:
+          cmd: lint:js
+      - name: Lint Markdown files
+        uses: borales/[email protected]
+        with:
+          cmd: lint:md

.github/workflows/test.yml

@@ -0,0 +1,17 @@
+name: Run tests
+
+on: [push]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install dependencies
+        uses: borales/[email protected]
+        with:
+          cmd: install
+      - name: Run unit tests
+        uses: borales/[email protected]
+        with:
+          cmd: test