to release v3.9.1

Author: brucefan1983

src/main_gpumd/main.cu

@@ -59,7 +59,7 @@ void print_welcome_information(void)
   printf("***************************************************************\n");
   printf("*                 Welcome to use GPUMD                        *\n");
   printf("*     (Graphics Processing Units Molecular Dynamics)          *\n");
-  printf("*                     Version 3.9                             *\n");
+  printf("*                    Version 3.9.1                            *\n");
   printf("*              This is the gpumd executable                   *\n");
   printf("***************************************************************\n");
   printf("\n");

src/main_nep/main.cu

@@ -70,7 +70,7 @@ void print_welcome_information(void)
   printf("***************************************************************\n");
   printf("*                 Welcome to use GPUMD                        *\n");
   printf("*    (Graphics Processing Units Molecular Dynamics)           *\n");
-  printf("*                     Version 3.9                             *\n");
+  printf("*                    Version 3.9.1                            *\n");
   printf("*              This is the nep executable                     *\n");
   printf("***************************************************************\n");
   printf("\n");