Add table of supported clouds to readme and docs (#584)

Author: parasj

README.md

@@ -17,7 +17,9 @@ You can use Skyplane to transfer data:
 * Between object stores across multiple cloud providers
 * Between local storage and cloud object stores
 
-Skyplane currently only supports MacOS and Linux. For Windows, first [install Linux on Windows with WSL](https://docs.microsoft.com/en-us/windows/wsl/install) to run Skyplane.
+Skyplane supports all major public clouds including AWS, Azure, and GCP. It can also transfer data between any combination of these clouds:
+
+<img src="docs/_static/supported-destinations.png" width="512" />
 
 # Getting started
 

docs/_static/supported-destinations.png

@@ -28,6 +28,10 @@ Copy a large dataset in the cloud in a minute, not hours:
    $ skyplane [sync/cp] [local/s3/gcp/azure]://mybucket/big_dataset [local/s3/gcp/azure]://mybucket2/
 
 
+Skyplane supports copying data between any major public cloud:
+
+.. image:: /_static/supported-destinations.png
+
 Contents
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