prettify paket.config

[adamralph]

fixes #1952

Before:

<configuration><credentials><token source="https://www.nuget.org" value="..." /></credentials></configuration>

After:

<?xml version="1.0" encoding="utf-16"?>
<configuration>
  <credentials>
    <token source="https://www.nuget.org" value="..." />
  </credentials>
</configuration>

Do you mind the addition of <?xml version="1.0" encoding="utf-16"?>?

[isaacabraham]

LGTM.

[forki]

cool. thanks!

[adamralph]

np.

Note the addition of <?xml version="1.0" encoding="utf-16"?>.