Replace Travis by Github Action (#1477)

Co-authored-by: Bastien Teinturier <31281497+t-bast@users.noreply.github.com>

.github/workflows/main.yml

@@ -0,0 +1,33 @@
+name: Build & Test
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up JDK 11
+      uses: actions/setup-java@v1
+      with:
+        java-version: 11
+
+    - name: Cache Maven dependencies
+      uses: actions/cache@v2
+      with:
+        path: ~/.m2
+        key: ${{ runner.os }}-m2-${{ hashFiles('**/pom.xml') }}
+        restore-keys: ${{ runner.os }}-m2
+
+    - name: Configure OS settings
+      run: echo "fs.file-max = 1024000" | sudo tee -a /etc/sysctl.conf
+
+    - name: Build with Maven
+      run: mvn clean test

README.md

@@ -1,6 +1,6 @@
 ![Eclair Logo](.readme/logo.png)
 
-[![Build Status](https://travis-ci.org/ACINQ/eclair.svg?branch=master)](https://travis-ci.org/ACINQ/eclair)
+[![Build Status](https://github.com/ACINQ/eclair/workflows/Build%20&%20Test/badge.svg)](https://github.com/ACINQ/eclair/actions?query=workflow%3A%22Build+%26+Test%22)
 [![codecov](https://codecov.io/gh/acinq/eclair/branch/master/graph/badge.svg)](https://codecov.io/gh/acinq/eclair)
 [![License](https://img.shields.io/badge/license-Apache%202.0-blue.svg)](LICENSE)
 [![Gitter chat](https://img.shields.io/badge/chat-on%20gitter-red.svg)](https://gitter.im/ACINQ/eclair)