Add setup-qemu action (#71)

Signed-off-by: CrazyMax <crazy-max@users.noreply.github.com>

setup-qemu/README.md

@@ -0,0 +1,51 @@
+## About
+
+GitHub Action to install [QEMU static binaries](https://github.com/multiarch/qemu-user-static).
+
+___
+
+* [Usage](#usage)
+  * [Quick start](#quick-start)
+* [Customizing](#customizing)
+  * [inputs](#inputs)
+* [Limitation](#limitation)
+
+## Usage
+
+```yaml
+name: ci
+
+on:
+  pull_request:
+    branches: master
+  push:
+    branches: master
+    tags:
+
+jobs:
+  qemu:
+    runs-on: ubuntu-latest
+    steps:
+      -
+        name: Checkout
+        uses: actions/checkout@v2
+      -
+        name: Set up QEMU
+        uses: docker/action/setup-qemu@v2
+        with:
+          qemu-version: latest
+```
+
+## Customizing
+
+### inputs
+
+Following inputs can be used as `step.with` keys
+
+| Name             | Type    | Default   | Description                        |
+|------------------|---------|-----------|------------------------------------|
+| `qemu-version`   | String  | `latest`  | [qemu-user-static](https://github.com/multiarch/qemu-user-static) version (Docker tag). Example: `4.2.0-7` |
+
+## Limitation
+
+This action is only available for Linux [virtual environments](https://help.github.com/en/articles/virtual-environments-for-github-actions#supported-virtual-environments-and-hardware-resources).