tests fail if not cloned as a git repo

[vtjnash]

Pkg.test fails: e.g. https://s3.amazonaws.com/julialang-reports/nanosoldier/pkgeval/by_date/2021-02/21/Coverage.1.7.0-DEV-d524f21917.log

     Testing Running tests...
┌ Warning: skipping local repo tests for Codecov, since not a git repo
└ @ Main ~/.julia/packages/Coverage/3V3Eo/test/runtests.jl:106
coveralls: Error During Test at /Users/jameson/.julia/packages/Coverage/3V3Eo/test/runtests.jl:430
  Got exception outside of a @test
  GitError(Code:ENOTFOUND, Class:Repository, could not find repository from '/Users/jameson/.julia/packages/Coverage/3V3Eo/test')