Add GitHub Actions

.github/workflows/ci.yaml

@@ -0,0 +1,23 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up JDK 1.8
+        uses: actions/setup-java@v2
+        with:
+          distribution: 'adopt'
+          java-version: '8'
+      - uses: actions/cache@v2
+        with:
+          path: ~/.m2/repository
+          key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
+          restore-keys: ${{ runner.os }}-maven-
+      - name: Build with Maven
+        run: mvn clean install
+      - name: Remove proj4j artifacts from cache
+        run: rm -rf $HOME/.m2/repository/org/locationtech/proj4j

README.md

@@ -1,4 +1,4 @@
-# Proj4J
+# Proj4J [![GitHub Action Status](https://github.com/locationtech/proj4j/workflows/CI/badge.svg)](https://github.com/locationtech/proj4j/actions) 
 
 Proj4J is a Java library for converting coordinates between different geospatial coordinate reference systems.
 It is designed to be compatible with `proj.4` parameters and derives some of its implementation from the `proj.4` sources.