Make tags query /git/refs/tags instead of /git/tags (#121)

There is an API endpoint /git/tags, but that only accepts SHA1 hashes.

Author: Arnav Sood

src/git/tag.jl

@@ -12,7 +12,7 @@ Tag(data::Dict) = json2github(Tag, data)
 namefield(tag::Tag) = tag.sha
 
 @api_default function tag(api::GitHubAPI, repo, tag_obj; options...)
-    result = gh_get_json(api, "/repos/$(name(repo))/git/tags/$(name(tag_obj))"; options...)
+    result = gh_get_json(api, "/repos/$(name(repo))/git/refs/tags/$(name(tag_obj))"; options...)
     return Tag(result)
 end
 

test/read_only_api_tests.jl

@@ -197,10 +197,15 @@ end
 end
 
 @testset "Tags and References" begin
+    # All tags in this repo are lightweight tags which are not covered by the API
+    # Maybe test in the future when we have a use case
     github_jl = Repo("JuliaWeb/GitHub.jl")
     ref = reference(github_jl, "heads/master"; auth=auth)
     @test ref.object["type"] == "commit"
 
-    # All tags in this repo are lightweight tags which are not covered by the API
-    # Maybe test in the future when we have a use case
+    # Tag API
+    reponame = "QuantEcon/Expectations.jl"
+    version = "v1.0.1"
+    exptag = tag(reponame, version)
+    @test isa(exptag, Tag)
 end