Add sponsorship message in C generator

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CLibcurlClientCodegen.java

@@ -898,4 +898,19 @@ public void postProcessFile(File file, String fileType) {
             }
         }
     }
+
+    @Override
+    public void postProcess() {
+        System.out.println("################################################################################");
+        System.out.println("# Thanks for using OpenAPI Generator.                                          #");
+        System.out.println("# Please consider donation to help us maintain this project \uD83D\uDE4F                 #");
+        System.out.println("# https://opencollective.com/openapi_generator/donate                          #");
+        System.out.println("#                                                                              #");
+        System.out.println("# This generator is contributed by Hemant Zope (https://github.com/zhemant)    #");
+        System.out.println("# and Niklas Werner (https://github.com/PowerOfCreation).                      #");
+        System.out.println("# Please support their work directly \uD83D\uDE4F                                        #");
+        System.out.println("# > Hemant Zope - https://www.patreon.com/zhemant                              #");
+        System.out.println("# > Niklas Werner - https://paypal.me/wernerdevelopment                        #");
+        System.out.println("################################################################################");
+    }
 }

samples/client/petstore/c/.openapi-generator/VERSION

@@ -1 +1 @@
-5.0.1-SNAPSHOT
+5.1.0-SNAPSHOT