[C++] Upload coverage data to codecov.io

[asfimport]

ARROW-27 (upload coverage data to coveralls.io) has failed moving forward. We can try codecov.io instead, another free code coverage hosting service.

Reporter: Antoine Pitrou / @pitrou
Assignee: Antoine Pitrou / @pitrou

PRs and other links:

• GitHub Pull Request #2023

_{Note: This issue was originally created as ARROW-2562. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
Here is an example coverage report. It shows the combined coverage results of running the C++, Python and Rust test suites:

https://codecov.io/gh/pitrou/arrow/list/b143005404c2af16cbb3f40c3f1564c3758f4fdb/

@wesm

[asfimport]

Antoine Pitrou / @pitrou:
Issue resolved by pull request 2023
#2023