Add option to run custom architecture (container platform) (#525)

* Add QEMU to run different architectures

* Update dependencies in `go.mod`

* Add `--container-architecture` flag to specify custom image architecture

Co-authored-by: Casey Lee <cplee@nektos.com>

.github/workflows/push.yml

@@ -18,6 +18,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
+    - name: Set up QEMU
+      uses: docker/setup-qemu-action@v1
     - uses: actions/setup-go@v1
       with:
         go-version: 1.14