fix(build): main migration

Author: Christian Compton

.travis.yml

@@ -40,7 +40,7 @@ deploy:
     skip_cleanup: true
     on:
       python: '3.6'
-      branch: master
+      branch: main
   - provider: pypi
     user: $PYPI_USER
     password: $PYPI_TOKEN

README.md

@@ -1,8 +1,8 @@
-[![Build Status](https://travis-ci.com/IBM/python-sdk-core.svg?branch=master)](https://travis-ci.com/IBM/python-sdk-core)
+[![Build Status](https://travis-ci.com/IBM/python-sdk-core.svg?branch=main)](https://travis-ci.com/IBM/python-sdk-core)
 [![PyPI - Python Version](https://img.shields.io/pypi/pyversions/ibm-cloud-sdk-core)](https://pypi.org/project/ibm-cloud-sdk-core/)
 [![Latest Stable Version](https://img.shields.io/pypi/v/ibm-cloud-sdk-core.svg)](https://pypi.python.org/pypi/ibm-cloud-sdk-core)
 [![CLA assistant](https://cla-assistant.io/readme/badge/ibm/python-sdk-core)](https://cla-assistant.io/ibm/python-sdk-core)
-[![semantic-release](https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg)](https://github.com/semantic-release/semantic-release)[![codecov](https://codecov.io/gh/IBM/python-sdk-core/branch/master/graph/badge.svg)](https://codecov.io/gh/IBM/python-sdk-core)
+[![semantic-release](https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg)](https://github.com/semantic-release/semantic-release)[![codecov](https://codecov.io/gh/IBM/python-sdk-core/branch/main/graph/badge.svg)](https://codecov.io/gh/IBM/python-sdk-core)
 
 # IBM Python SDK Core Version 3.5.1
 This project contains core functionality required by Python code generated by the IBM Cloud OpenAPI SDK Generator