Incorrect certificate file extension

https://github.com/Azure-Samples/ms-identity-python-daemon/tree/master/2-Call-MsGraph-WithCertificate

Please see step 4 under 'Register the client app (daemon-console)'

> Click on Upload certificate and, in click the browse button on the right to select the certificate you just exported (server.pem or your existing certificate)

I believe this should actually refer to `server.crt`. The instruction conflicts with the wording in the previous section:

> You will have to upload this certificate (server.crt) on Azure Portal (See next step). Once you save this certificate, the portal will give you the thumbprint of this certificate which is needed in the acquire token call. The key will be the server.pem key you generated in the first step.