Update version to `3.1.0RC`.

README.md

@@ -20,7 +20,7 @@ of the Ministry of Economy, Trade and Industry of Japan.
 
 ## How to get mruby
 
-The stable version 3.0.0 of mruby can be downloaded via the following URL: [https://github.com/mruby/mruby/archive/3.0.0.zip](https://github.com/mruby/mruby/archive/3.0.0.zip)
+The release candidate version 3.1.0 of mruby can be downloaded via the following URL: [https://github.com/mruby/mruby/archive/3.1.0-rc.zip](https://github.com/mruby/mruby/archive/3.1.0-rc.zip)
 
 The latest development version of mruby can be downloaded via the following URL: [https://github.com/mruby/mruby/zipball/master](https://github.com/mruby/mruby/zipball/master)
 

include/mruby/version.h

@@ -27,7 +27,7 @@ MRB_BEGIN_DECL
 /*
  * The version of Ruby used by mruby.
  */
-#define MRUBY_RUBY_VERSION "3.0"
+#define MRUBY_RUBY_VERSION "3.1"
 
 /*
  * Ruby engine.
@@ -42,7 +42,7 @@ MRB_BEGIN_DECL
 /*
  * Minor release version number.
  */
-#define MRUBY_RELEASE_MINOR 0
+#define MRUBY_RELEASE_MINOR 1
 
 /*
  * Tiny release version number.
@@ -57,7 +57,7 @@ MRB_BEGIN_DECL
 /*
  * Patch level string. (optional)
  */
-#define MRUBY_PATCHLEVEL_STR ""
+#define MRUBY_PATCHLEVEL_STR "RC"
 
 #ifndef MRUBY_PATCHLEVEL_STR
 # if MRUBY_PATCHLEVEL < 0
@@ -80,17 +80,17 @@ MRB_BEGIN_DECL
 /*
  * Release year.
  */
-#define MRUBY_RELEASE_YEAR 2021
+#define MRUBY_RELEASE_YEAR 2022
 
 /*
  * Release month.
  */
-#define MRUBY_RELEASE_MONTH 3
+#define MRUBY_RELEASE_MONTH 1
 
 /*
  * Release day.
  */
-#define MRUBY_RELEASE_DAY 5
+#define MRUBY_RELEASE_DAY 7
 
 /*
  * Release date as a string.