Remove Travis configuration

All CI tasks are now handled by Azure Pipelines.

Author: lupino3

.travis.yml

@@ -1,10 +1,8 @@
 # cmd-call-graph
 
 [![Build Status](https://dev.azure.com/cmd-call-graph/cmd-call-graph/_apis/build/status/Microsoft.cmd-call-graph?branchName=master)](https://dev.azure.com/cmd-call-graph/cmd-call-graph/_build/latest?definitionId=1?branchName=master)
-[![Build Status](https://api.travis-ci.org/Microsoft/cmd-call-graph.svg?branch=master)](http://travis-ci.org/Microsoft/cmd-call-graph)
 [![PyPI](https://img.shields.io/pypi/v/cmd-call-graph.svg)](https://pypi.org/project/cmd-call-graph/)
 
-
 A simple tool to generate a call graph for calls within Windows CMD (batch) files.
 
 The tool is available on PyPI: https://pypi.org/project/cmd-call-graph/