Implemented GitHub Actions support

.github/workflows/build.yml

@@ -0,0 +1,24 @@
+name: Build
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v1
+
+      - name: cmake
+        run: cmake .
+
+      - name: make
+        run: make -j4

README.md

@@ -1,6 +1,8 @@
 JniHelpers
 ==========
 
+![Build](https://github.com/leozz37/JniHelpers/workflows/Build/badge.svg)
+
 JniHelpers is a library designed to facilitate writing JNI code with C++.
 It provides the following features: