Update erasure README with supported architecture list

pkg/encoding/erasure/README.md

@@ -7,3 +7,19 @@ Erasure is an open source Golang library written on top of ISAL (Intel Intellige
 * [Build Dependencies](./BUILDDEPS.md)
 * [Development Workflow](./CONTRIBUTING.md#developer-guidelines)
 * [Developer discussions and bugs](https://github.com/Minio-io/erasure/issues)
+
+### Supported platforms
+
+| Name  | Supported |
+| ------------- | ------------- |
+| Linux  | Yes  |
+| Windows | Not yet |
+| Mac OSX | Yes |
+
+### Supported architectures
+
+| Arch | Supported |
+| ------------- | ------------- |
+| x86-64 | Yes |
+| arm64 | Not yet|
+| i386 | Never |