docs: Bump Go version in README and add acceptance tests

Signed-off-by: Federico Barcelona <[email protected]>

Author: tembleking

README.md

@@ -32,7 +32,7 @@ If you're building the provider, follow the instructions to [install it as a plu
 Developing the Provider
 ---------------------------
 
-If you wish to work on the provider, you'll first need [Go](http://www.golang.org) installed on your machine (version 1.9+ is *required*). You'll also need to correctly setup a [GOPATH](http://golang.org/doc/code.html#GOPATH), as well as adding `$GOPATH/bin` to your `$PATH`.
+If you wish to work on the provider, you'll first need [Go](http://www.golang.org) installed on your machine (version 1.13+ is *required*). You'll also need to correctly setup a [GOPATH](http://golang.org/doc/code.html#GOPATH), as well as adding `$GOPATH/bin` to your `$PATH`.
 
 To compile the provider, run `make build`. This will build the provider and put the provider binary in the `$GOPATH/bin` directory.
 
@@ -48,3 +48,9 @@ In order to test the provider, you can simply run `make test`.
 ```sh
 $ make test
 ```
+
+If you want to execute the acceptance tests, you can run `make testacc`. Please note that you need a token for Monitor and Secure, and since the acceptance tests create real infrastructure you should execute them in an environment where you can remove the resorces easily.
+
+```sh
+$ make testacc
+```