Add regression test that all imports keep being explicit.

Project.toml

@@ -10,10 +10,12 @@ SHA = "ea8e919c-243c-51af-8825-aaa63cd721ce"
 UUIDs = "cf7118a7-6976-5b1a-9a39-7adc72f591a4"
 
 [compat]
+ExplicitImports = "1.5"
 julia = "1.1"
 
 [extras]
+ExplicitImports = "7d51a73a-1435-4ff3-83d9-f097790105c7"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["Test"]
+test = ["ExplicitImports", "Test"]

test/runtests.jl

@@ -1,9 +1,15 @@
 import RegistryTools
 using Test: @testset, @test
+using ExplicitImports: check_no_implicit_imports, check_no_stale_explicit_imports
 
 @testset "RegistryTools" begin
 
 include("regedit.jl")
 include("compress.jl")
 
+@testset "ExplicitImports" begin
+    @test isnothing(check_no_implicit_imports(RegistryTools))
+    @test isnothing(check_no_stale_explicit_imports(RegistryTools))
+end
+
 end