build(ci): change from travis to github actions

Move away from travis and use GitHub Actions instead.

My reasoning for this is because then our CI is in the same place as our code and also because GitHub Actions allows for more possibilities then travis.

.github/workflows/ci.yml

@@ -0,0 +1,21 @@
+name: CI
+on: [push, pull_request]
+jobs:
+  test:
+    name: Test build process on node ${{ matrix.node_version }}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node_version: [8, 10, 11, 12]
+    steps:
+    - uses: actions/checkout@v1
+    - name: Use Node.js ${{ matrix.node-version }}
+      uses: actions/setup-node@v1
+      with:
+        node-version: ${{ matrix.node-version }}
+    - name: pre-install
+      run: sh preinstall.sh
+    - name: install dependencies
+      run: npm install
+    - name: gulp build
+      run: npx gulp build