Use a coverage project for code coverage submission.

.gitignore

@@ -2,4 +2,5 @@
 *.jl.*.cov
 *.jl.mem
 *.DS_Store
-Manifest.toml
+/Manifest.toml
+/test/coverage/Manifest.toml

.travis.yml

@@ -20,9 +20,9 @@ jobs:
       os: linux
       script:
         - julia docs/make.jl
+        - julia --project=test/coverage -e 'using Pkg; Pkg.instantiate()'
+        - julia --project=test/coverage test/coverage/coverage.jl
 notifications:
   email: false
 git:
   depth: 99999999
-after_success:
-  - julia test/coverage.jl

test/coverage/Project.toml

@@ -0,0 +1,2 @@
+[deps]
+Coverage = "a2441757-f6aa-5fb2-8edb-039e3f45d037"

test/coverage/coverage.jl

@@ -1,6 +1,5 @@
-using Pkg
-Pkg.add("Coverage")
 using Coverage
-cd(joinpath(@__DIR__, "..")) do
+
+cd(joinpath(@__DIR__, "..", "..")) do
     Codecov.submit(Codecov.process_folder())
 end