Updated git clone URL in README.md file[For Issue #11]

[ShehanAT]

For Issue:

#11

Description:

The following section in the README.md file has the incorrect URL for cloning the application:

git clone https://github.com/joshuamdeguzman/semaphoreci_flutter_demo

What Changed:

I updated the above URL with the correct clone URL in the README.md file:

git clone https://github.com/semaphoreci-demos/semaphore-demo-flutter2

How Has This Been Tested?

I didn't run any tests as this is only a README.md file change.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

[markoa]

Thank you @ShehanAT