graphlient: Add signatures (#987)

* ./bin/init_new_gem graphlient

* Add rbs

* Add test

* Remove empty files

* Fix rubocop offenses

```
Offenses:

graphlient.rbs:3:70: C: [Correctable] RBS/Style/InstanceWithInstance: Use self instead of instance.
    def initialize: (String url, ?Hash[Symbol, untyped] options) ?{ (instance) -> void } -> void
                                                                     ^^^^^^^^
graphlient.rbs:7:7: C: [Correctable] RBS/Layout/OverloadIndentation: Indent the | to the first :
      | (?Hash[Symbol | String, untyped]? variables) { () -> untyped } -> untyped
      ^

1 file inspected, 2 offenses detected, 2 offenses autocorrectable
```

Author: sue445

gems/graphlient/.rubocop.yml

@@ -0,0 +1,19 @@
+# This configuration inherits from /.rubocop.yml.
+# You can configure RBS style of this gem.
+# This file is used on CI. It is configured to automatically
+# make rubocop suggestions on pull requests for this gem.
+# If you do not like the style enforcement, you should remove this file.
+inherit_from: ../../.rubocop.yml
+
+##
+# If you want to customize the style, please consult with the gem reviewers.
+# You can see the list of cops at https://github.com/ksss/rubocop-on-rbs/blob/main/docs/modules/ROOT/pages/cops.adoc
+
+RBS/Layout:
+  Enabled: true
+
+RBS/Lint:
+  Enabled: true
+
+RBS/Style:
+  Enabled: true

gems/graphlient/0.8/_test/test.rb

@@ -0,0 +1,64 @@
+require "graphlient"
+
+client = Graphlient::Client.new('https://test-graphql.biz/graphql',
+  headers: {
+    'Authorization' => 'Bearer 123'
+  },
+  http_options: {
+    read_timeout: 20,
+    write_timeout: 30
+  }
+)
+
+# simple query
+response = client.query <<~GRAPHQL
+  query {
+    invoice(id: 10) {
+      id
+      total
+      line_items {
+        price
+        item_type
+      }
+    }
+  }
+GRAPHQL
+
+response = client.query do
+  # steep:ignore:start
+  query do
+    invoice(id: 10) do
+      id
+      total
+      line_items do
+        price
+        item_type
+      end
+    end
+  end
+  # steep:ignore:end
+end
+
+# Executing Parameterized Queries and Mutations
+query = <<-GRAPHQL
+  query($ids: [Int]) {
+    invoices(ids: $ids) {
+      id
+      fee_in_cents
+    }
+  }
+GRAPHQL
+variables = { ids: [42] }
+
+client.query(query, variables)
+
+client.query(ids: [42]) do
+  # steep:ignore:start
+  query(ids: [:int]) do
+    invoices(ids: :ids) do
+      id
+      fee_in_cents
+    end
+  end
+  # steep:ignore:end
+end

gems/graphlient/0.8/graphlient.rbs

@@ -0,0 +1,9 @@
+module Graphlient
+  class Client
+    def initialize: (String url, ?Hash[Symbol, untyped] options) ?{ (self) -> void } -> void
+
+    # FIXME: return GraphQL::Client::Response instead of untyped
+    def query: (String query, ?Hash[Symbol | String, untyped]? variables) -> untyped
+             | (?Hash[Symbol | String, untyped]? variables) { () -> untyped } -> untyped
+  end
+end