* Set up CI with Azure Pipelines

[skip ci]

* Update azure-pipelines.yml for Azure Pipelines

* Update azure-pipelines.yml for Azure Pipelines

* fix for azure-pipeline

* polish azure-pipelines

* try assembly on real data with azure pipelines

* fix segmentation fault when there exits length-0 sequences

* remove an incorrect assert in UnitigGraph::Refresh

* add partial assembly to azure pipelines

* add codecov report to azure pipeline

* add more tests and update codecov setting

* release 1.2.9