Fix label parameters validation

No parameter are mandatory for updating an existing label, but when
creating one, a name is required.
https://docs.github.com/en/rest/reference/issues#create-a-label

Author: smortex

lib/github_api/client/issues/labels.rb

@@ -80,7 +80,7 @@ def get(*args)
     def create(*args)
       arguments(args, required: [:user, :repo]) do
         permit VALID_LABEL_INPUTS
-        assert_required VALID_LABEL_INPUTS
+        assert_required %w[ name color ]
       end
 
       post_request("/repos/#{arguments.user}/#{arguments.repo}/labels", arguments.params)
@@ -103,7 +103,6 @@ def create(*args)
     def update(*args)
       arguments(args, required: [:user, :repo, :label_name]) do
         permit VALID_LABEL_INPUTS
-        assert_required VALID_LABEL_INPUTS
       end
 
       patch_request("/repos/#{arguments.user}/#{arguments.repo}/labels/#{arguments.label_name}", arguments.params)

spec/github/client/issues/labels/update_spec.rb

@@ -26,18 +26,6 @@
     let(:body) { fixture('issues/label.json') }
     let(:status) { 200 }
 
-    it "should fail to create resource if 'name' input is missing" do
-      expect {
-        subject.update user, repo, label_id, inputs.except('name')
-      }.to raise_error(Github::Error::RequiredParams)
-    end
-
-    it "should fail to create resource if 'color' input is missing" do
-      expect {
-        subject.update user, repo, label_id, inputs.except('color')
-      }.to raise_error(Github::Error::RequiredParams)
-    end
-
     it "should update resource successfully" do
       subject.update user, repo, label_id, inputs
       expect(a_patch(request_path).with(body: inputs)).to have_been_made