CI: use GitHub Actions

Use GitHub actions to run golang-ci-lint, cross, and test.

The "Test()" target in Mage was a plain "go test -v ./...", and should be
portable to other CI systems if needed; running it through the mage file
effectively resulted in "compile a go binary to run go".

The "Lint()" target in Mage relied on Travis CI setting up Golang-CI lint
before it was executed, which required bash. Moving it to GitHub actions
also allowed it to be run on Windows. Golang CI can still be run locally
either through the mage file (which is kept for now), or running
`golangci-lint run ./...` after installing golangci-lint.

The "CrossBuild() Mage target is still used to perform cross-compile, as it
contains code to generate the GOOS/GOARCH matrix, which makes it easier
to run locally.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

.github/workflows/ci.yaml

@@ -0,0 +1,61 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+jobs:
+
+  lint:
+    name: Golang-CI Lint
+    timeout-minutes: 10
+    strategy:
+      matrix:
+        platform: [ubuntu-latest, windows-latest]
+    runs-on: ${{ matrix.platform }}
+    steps:
+      - uses: actions/checkout@v2
+      - uses: golangci/golangci-lint-action@v2
+        with:
+          # must be specified without patch version
+          version: v1.36
+  cross:
+    name: Cross
+    timeout-minutes: 10
+    strategy:
+      matrix:
+        go-version: [1.16.x]
+        platform: [ubuntu-latest]
+    runs-on: ${{ matrix.platform }}
+    steps:
+      - name: Install Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: ${{ matrix.go-version }}
+      - name: Checkout code
+        uses: actions/checkout@v2
+      - name: Cross
+        working-directory: ci
+        run: go run mage.go -v -w ../ crossBuild
+
+  test:
+    name: Unit test
+    timeout-minutes: 10
+    strategy:
+      matrix:
+        go-version: [1.14.x, 1.15.x, 1.16.x]
+        platform: [ubuntu-latest, windows-latest]
+    runs-on: ${{ matrix.platform }}
+    steps:
+    - name: Install Go
+      uses: actions/setup-go@v2
+      with:
+        go-version: ${{ matrix.go-version }}
+    - name: Checkout code
+      uses: actions/checkout@v2
+    - name: Test
+      run: go test -race -v ./...

README.md

@@ -1,4 +1,4 @@
-# Logrus <img src="http://i.imgur.com/hTeVwmJ.png" width="40" height="40" alt=":walrus:" class="emoji" title=":walrus:"/> [![Build Status](https://travis-ci.org/sirupsen/logrus.svg?branch=master)](https://travis-ci.org/sirupsen/logrus) [![GoDoc](https://godoc.org/github.com/sirupsen/logrus?status.svg)](https://godoc.org/github.com/sirupsen/logrus)
+# Logrus <img src="http://i.imgur.com/hTeVwmJ.png" width="40" height="40" alt=":walrus:" class="emoji" title=":walrus:"/> [![Build Status](https://github.com/sirupsen/logrus/workflows/CI/badge.svg)](https://github.com/sirupsen/logrus/actions?query=workflow%3ACI) [![Build Status](https://travis-ci.org/sirupsen/logrus.svg?branch=master)](https://travis-ci.org/sirupsen/logrus) [![GoDoc](https://godoc.org/github.com/sirupsen/logrus?status.svg)](https://godoc.org/github.com/sirupsen/logrus)
 
 Logrus is a structured logger for Go (golang), completely API compatible with
 the standard library logger.