Add a simple github workflow

Author: cmeister2

.github/workflows/ci.yml

@@ -0,0 +1,38 @@
+name: CI
+'on':
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+jobs:
+  Build:
+    runs-on: '${{ matrix.os }}'
+    strategy:
+      matrix:
+        os:
+          - ubuntu-18.04
+        tool:
+          - mainline
+    steps:
+      - name: Install dependencies (Ubuntu)
+        run: >-
+          sudo apt-get update
+
+          sudo apt-get install -y \
+            clang-3.7 \
+            krb5-user \
+            lcov \
+            libc-ares-dev \
+            libev-dev \
+            libidn2-0-dev \
+            libssh2-1-dev \
+            libstdc++-4.8-dev \
+            pkg-config \
+            git \
+            make \
+            autoconf \
+            libtool
+      - uses: actions/checkout@v2
+      - run: './${{ matrix.tool }}.sh'