README: mention 20.03 (#51)

Author: asymmetric

google_image_nixos/README.md

@@ -65,7 +65,7 @@ PR as well!
 | gcp\_project\_id | The ID of the project in which the resource belongs. If it is not provided, the provider project is used. | `string` | `""` | no |
 | licenses | A list of license URIs to apply to this image. Changing this forces a new resource to be created. | `list(string)` | <pre>[<br>  "https://www.googleapis.com/compute/v1/projects/vm-options/global/licenses/enable-vmx"<br>]</pre> | no |
 | nixos\_version | The NixOS version to use. Eg: 18.09 | `string` | `"latest"` | no |
-| url\_map | A map of release series to actual releases | `map(string)` | <pre>{<br>  "14.12": "https://nixos-cloud-images.storage.googleapis.com/nixos-14.12.471.1f09b77-x86_64-linux.raw.tar.gz",<br>  "15.09": "https://nixos-cloud-images.storage.googleapis.com/nixos-15.09.425.7870f20-x86_64-linux.raw.tar.gz",<br>  "16.03": "https://nixos-cloud-images.storage.googleapis.com/nixos-image-16.03.847.8688c17-x86_64-linux.raw.tar.gz",<br>  "17.03": "https://nixos-cloud-images.storage.googleapis.com/nixos-image-17.03.1082.4aab5c5798-x86_64-linux.raw.tar.gz",<br>  "18.03": "https://nixos-cloud-images.storage.googleapis.com/nixos-image-18.03.132536.fdb5ba4cdf9-x86_64-linux.raw.tar.gz",<br>  "18.09": "https://nixos-cloud-images.storage.googleapis.com/nixos-image-18.09.1228.a4c4cbb613c-x86_64-linux.raw.tar.gz",<br>  "latest": "https://nixos-cloud-images.storage.googleapis.com/nixos-image-18.09.1228.a4c4cbb613c-x86_64-linux.raw.tar.gz"<br>}</pre> | no |
+| url\_map | A map of release series to actual releases | `map(string)` | <pre>{<br>  "14.12": "https://nixos-cloud-images.storage.googleapis.com/nixos-14.12.471.1f09b77-x86_64-linux.raw.tar.gz",<br>  "15.09": "https://nixos-cloud-images.storage.googleapis.com/nixos-15.09.425.7870f20-x86_64-linux.raw.tar.gz",<br>  "16.03": "https://nixos-cloud-images.storage.googleapis.com/nixos-image-16.03.847.8688c17-x86_64-linux.raw.tar.gz",<br>  "17.03": "https://nixos-cloud-images.storage.googleapis.com/nixos-image-17.03.1082.4aab5c5798-x86_64-linux.raw.tar.gz",<br>  "18.03": "https://nixos-cloud-images.storage.googleapis.com/nixos-image-18.03.132536.fdb5ba4cdf9-x86_64-linux.raw.tar.gz",<br>  "18.09": "https://nixos-cloud-images.storage.googleapis.com/nixos-image-18.09.1228.a4c4cbb613c-x86_64-linux.raw.tar.gz",<br>  "20.03": "https://nixos-images.storage.googleapis.com/google-cloud-nixos-20.03.1639.73e73c7d6b5.raw.tar.gz",<br> "latest": "https://nixos-images.storage.googleapis.com/google-cloud-nixos-20.03.1639.73e73c7d6b5.raw.tar.gz"<br>}</pre> | no |
 
 ## Outputs