Rspec lint the gorouter template tests

In #331, we added
some new template tests. They pass but contained some minor linting
issues.

Fixes:
```
spec/gorouter_templates_spec.rb:176:45: C: [Correctable] Style/WordArray: Use %w or %W for an array of words.
          'hop_by_hop_headers_to_filter' => ["X-ME", "X-Foo"],
                                            ^^^^^^^^^^^^^^^^^
spec/gorouter_templates_spec.rb:176:46: C: [Correctable] Style/StringLiterals: Prefer single-quoted strings when you don't need string interpolation or special symbols.
          'hop_by_hop_headers_to_filter' => ["X-ME", "X-Foo"],
                                             ^^^^^^
spec/gorouter_templates_spec.rb:176:54: C: [Correctable] Style/StringLiterals: Prefer single-quoted strings when you don't need string interpolation or special symbols.
          'hop_by_hop_headers_to_filter' => ["X-ME", "X-Foo"],
                                                     ^^^^^^^
spec/gorouter_templates_spec.rb:374:69: C: [Correctable] Style/WordArray: Use %w or %W for an array of words.
          expect(parsed_yaml['hop_by_hop_headers_to_filter']).to eq(["X-ME","X-Foo"])
                                                                    ^^^^^^^^^^^^^^^^
spec/gorouter_templates_spec.rb:374:70: C: [Correctable] Style/StringLiterals: Prefer single-quoted strings when you don't need string interpolation or special symbols.
          expect(parsed_yaml['hop_by_hop_headers_to_filter']).to eq(["X-ME","X-Foo"])
                                                                     ^^^^^^
spec/gorouter_templates_spec.rb:374:76: C: [Correctable] Layout/SpaceAfterComma: Space missing after comma.
          expect(parsed_yaml['hop_by_hop_headers_to_filter']).to eq(["X-ME","X-Foo"])
                                                                           ^
spec/gorouter_templates_spec.rb:374:77: C: [Correctable] Style/StringLiterals: Prefer single-quoted strings when you don't need string interpolation or special symbols.
          expect(parsed_yaml['hop_by_hop_headers_to_filter']).to eq(["X-ME","X-Foo"])

```

Author: jrussett

spec/gorouter_templates_spec.rb

@@ -173,7 +173,7 @@
           'enable_proxy' => false,
           'force_forwarded_proto_https' => false,
           'sanitize_forwarded_proto' => false,
-          'hop_by_hop_headers_to_filter' => ["X-ME", "X-Foo"],
+          'hop_by_hop_headers_to_filter' => %w[X-ME X-Foo],
           'suspend_pruning_if_nats_unavailable' => false,
           'max_idle_connections' => 100,
           'keep_alive_probe_interval' => '1s',
@@ -371,7 +371,7 @@
 
       describe 'hop_by_hop_headers_to_filter' do
         it 'should set hop_by_hop_headers_to_filter' do
-          expect(parsed_yaml['hop_by_hop_headers_to_filter']).to eq(["X-ME","X-Foo"])
+          expect(parsed_yaml['hop_by_hop_headers_to_filter']).to eq(%w[X-ME X-Foo])
         end
       end