fix(crystal): use Spectator shard to run tests (described_class is not available in Crystal std lib)

Author: n-rodriguez

modules/openapi-generator/src/main/resources/crystal/api_test.mustache

@@ -7,7 +7,8 @@ require "time"
 # Unit tests for {{moduleName}}::{{classname}}
 # Automatically generated by openapi-generator (https://openapi-generator.tech)
 # Please update as you see appropriate
-{{#operations}}describe "{{classname}}" do
+{{#operations}}
+Spectator.describe "{{classname}}" do
   describe "test an instance of {{classname}}" do
     it "should create an instance of {{classname}}" do
       api_instance = {{moduleName}}::{{classname}}.new

modules/openapi-generator/src/main/resources/crystal/configuration_spec.mustache

@@ -4,7 +4,7 @@
 
 require 'spec_helper'
 
-describe {{moduleName}}::Configuration do
+Spectator.describe {{moduleName}}::Configuration do
   let(:config) { {{moduleName}}::Configuration.default }
 
   before(:each) do

modules/openapi-generator/src/main/resources/crystal/model_test.mustache

@@ -9,7 +9,7 @@ require "time"
 # Please update as you see appropriate
 {{#models}}
 {{#model}}
-describe {{moduleName}}::{{classname}} do
+Spectator.describe {{moduleName}}::{{classname}} do
 {{^oneOf}}
 
   describe "test an instance of {{classname}}" do

modules/openapi-generator/src/main/resources/crystal/shard.mustache

@@ -16,5 +16,8 @@ development_dependencies:
     version: ~>1.5.0
   ameba:
     github: crystal-ameba/ameba
+  spectator:
+    gitlab: arctic-fox/spectator
+    version: ~> 0.12.0
 
 license: {{{shardLicense}}}

modules/openapi-generator/src/main/resources/crystal/spec_helper.mustache

@@ -1,7 +1,7 @@
 # {{#lambdaPrefixWithHash}}{{> api_info}}{{/lambdaPrefixWithHash}}
 
 # load modules
-require "spec"
+require "spectator"
 require "json"
 require "../src/{{{shardName}}}"