Add Code Coverage to PR's

[kggilmer]

Java v2 SDK is using codecov.io which automatically adds a coverage analysis to PR's . It would be nice to integrate this if we can to our repo(s). We need to see if there is an enterprise account already being paid for, see if we can use it, etc.

internal id: 172765016

[kggilmer]

Moving to dev preview since this will be easier once the repo's are public (Aaron Todd - Jan 4, 2021)

[lauzadis]

Java v2 appears to only be using SonarCloud's code coverage offering now.