🔖 set version to 3.9.1

doc/Doxyfile

@@ -5,7 +5,7 @@
 #---------------------------------------------------------------------------
 DOXYFILE_ENCODING      = UTF-8
 PROJECT_NAME           = "JSON for Modern C++"
-PROJECT_NUMBER         = 3.9.0
+PROJECT_NUMBER         = 3.9.1
 PROJECT_BRIEF          =
 PROJECT_LOGO           =
 OUTPUT_DIRECTORY       = .

doc/examples/README.link

@@ -1 +1 @@
-<a target="_blank" href="https://wandbox.org/permlink/shE8T6phAQiEzAad"><b>online</b></a>
+<a target="_blank" href="https://wandbox.org/permlink/UYcLkpu1GaaAO2Cp"><b>online</b></a>

doc/examples/meta.output

@@ -11,7 +11,7 @@
     "version": {
         "major": 3,
         "minor": 9,
-        "patch": 0,
-        "string": "3.9.0"
+        "patch": 1,
+        "string": "3.9.1"
     }
 }

doc/index.md

@@ -332,4 +332,4 @@ Note that this table only lists those exceptions thrown due to the type. For ins
 @author [Niels Lohmann](http://nlohmann.me)
 @see https://github.com/nlohmann/json to download the source code
 
-@version 3.9.0
+@version 3.9.1