Update wrong module requirement versions

The list of module requirement versions is wrong and it prevents installing the module. 

Steps to reproduce:

Method 1:

1. Build the module
2. Install the omod file from the module installation window

Method 2:

1. Navigate to the module installation view
2. Search for 'DhisConnector' and click install

To resolve:

Update the module requirements with the correct versions. (main pom file)

The correct versions are as follows:

• Reporting: 1.20.0
• Calculation: 1.2
• Reporting Rest: 1.11.0
• Webservices Rest: 2.29.0
• Serialization Xstream: 0.2.14

 PR - https://github.com/openmrs/openmrs-module-dhisconnector/pull/9