Fix Opencover install
Fix Opencover install

fixes:

> Attempting to gather dependency information for package 'OpenCover.4.6.519' with respect to project 'C:\projects\nlogweb', targeting 'Any,Version=v0.0'
Gathering dependency information took 251.85 ms
Attempting to resolve dependencies for package 'OpenCover.4.6.519' with DependencyBehavior 'Lowest'
Unable to find package 'NLog.Web'. Existing packages must be restored before performing an install or update.
Command exited with code 1
NLog/NLog.Web