dependency(core): update requests minimal version required

[marcos-sinch]

Bumps the minimum required version of the requests dependency to >=2.0.0.

No breaking change for existing users.

[JPPortier]

Could you update the CHANGELOG file please: https://github.com/sinch/sinch-sdk-python/blob/feature/DEVEXP-1412-dependabot-vulnerability/CHANGELOG.md
Then when release will be performed all information summarize the release notes will be ready and available within git too for anyone

[marcos-sinch]

Could you update the CHANGELOG file please: https://github.com/sinch/sinch-sdk-python/blob/feature/DEVEXP-1412-dependabot-vulnerability/CHANGELOG.md Then when release will be performed all information summarize the release notes will be ready and available within git too for anyone

ok, i will do it in all the branches