Change release version to v3.0.3

Author: Felipe Zimmerle

CHANGES

@@ -1,5 +1,5 @@
-v3.0.3 - YYYY-MMM-DD (to be released)
--------------------------------------
+v3.0.3 - 2018-Nov-05
+--------------------
 
  - Fix double macros bug
    [Issue #1943 - @supplient, @zimmerle]

headers/modsecurity/modsecurity.h

@@ -190,7 +190,7 @@ namespace modsecurity {
 
 #define MODSECURITY_MAJOR "3"
 #define MODSECURITY_MINOR "0"
-#define MODSECURITY_PATCHLEVEL "2"
+#define MODSECURITY_PATCHLEVEL "3"
 #define MODSECURITY_TAG ""
 #define MODSECURITY_TAG_NUM "100"