Update configuration for frozen-string-literal (#1971)

In a future Ruby version strings will be frozen by default.
You can simulate the new behavior with RUBYOPT="--enable-frozen-string-literal".
With this enabled the url from configuration is mutated by gsub!.
We can avoid this by marking these strings as mutable.

Co-authored-by: jack-edmonds-dd <jack.edmonds@datadoghq.com>

Author: HParker

lib/datadog_api_client/configuration.rb

@@ -346,7 +346,7 @@ def auth_settings
     def server_settings
       [
         {
-          url: "https://{subdomain}.{site}",
+          url: +"https://{subdomain}.{site}",
           description: "No description provided",
           variables: {
             site: {
@@ -368,7 +368,7 @@ def server_settings
           }
         },
         {
-          url: "{protocol}://{name}",
+          url: +"{protocol}://{name}",
           description: "No description provided",
           variables: {
             name: {
@@ -382,7 +382,7 @@ def server_settings
           }
         },
         {
-          url: "https://{subdomain}.{site}",
+          url: +"https://{subdomain}.{site}",
           description: "No description provided",
           variables: {
             site: {
@@ -402,7 +402,7 @@ def operation_server_settings
       {
         "v1.get_ip_ranges": [
           {
-            url: "https://{subdomain}.{site}",
+            url: +"https://{subdomain}.{site}",
             description: "No description provided",
             variables: {
               site: {
@@ -424,7 +424,7 @@ def operation_server_settings
             }
           },
           {
-            url: "{protocol}://{name}",
+            url: +"{protocol}://{name}",
             description: "No description provided",
             variables: {
               name: {
@@ -438,19 +438,19 @@ def operation_server_settings
             }
           },
           {
-            url: "https://{subdomain}.datadoghq.com",
+            url: +"https://{subdomain}.datadoghq.com",
             description: "No description provided",
             variables: {
               subdomain: {
                 description: "The subdomain where the API is deployed.",
                 default_value: "ip-ranges",
               }
             }
-          }  
+          }
         ],
         "v1.submit_log": [
           {
-            url: "https://{subdomain}.{site}",
+            url: +"https://{subdomain}.{site}",
             description: "No description provided",
             variables: {
               site: {
@@ -472,7 +472,7 @@ def operation_server_settings
             }
           },
           {
-            url: "{protocol}://{name}",
+            url: +"{protocol}://{name}",
             description: "No description provided",
             variables: {
               name: {
@@ -486,7 +486,7 @@ def operation_server_settings
             }
           },
           {
-            url: "https://{subdomain}.{site}",
+            url: +"https://{subdomain}.{site}",
             description: "No description provided",
             variables: {
               site: {
@@ -498,11 +498,11 @@ def operation_server_settings
                 default_value: "http-intake.logs",
               }
             }
-          }  
+          }
         ],
         "v2.submit_log": [
           {
-            url: "https://{subdomain}.{site}",
+            url: +"https://{subdomain}.{site}",
             description: "No description provided",
             variables: {
               site: {
@@ -524,7 +524,7 @@ def operation_server_settings
             }
           },
           {
-            url: "{protocol}://{name}",
+            url: +"{protocol}://{name}",
             description: "No description provided",
             variables: {
               name: {
@@ -538,7 +538,7 @@ def operation_server_settings
             }
           },
           {
-            url: "https://{subdomain}.{site}",
+            url: +"https://{subdomain}.{site}",
             description: "No description provided",
             variables: {
               site: {
@@ -550,7 +550,7 @@ def operation_server_settings
                 default_value: "http-intake.logs",
               }
             }
-          }  
+          }
         ],
       }
     end
@@ -603,4 +603,4 @@ def to_hash
     end
   end
 
-end
+end