Versionbump: Blender 2.91 release

Referenced by issue #93741, Error importing OBJ or STL
Referenced by issue #88570, Regression: Crash when saving after pressing ctrl+S twice.
Referenced by issue #85896, Weight Paint Mode Redo Panel Problems
Referenced by issue #85253, Reproducible Crash when Projecting UVs after Merging by Distance ("Removing Doubles") from Live Home 3D Export
Referenced by issue #84839, EEVEE viewport poor playback performance with RTX 3090
Referenced by issue #84783, crashes when Mac wakes up
Referenced by issue #84620, Blender 2.91 won't open on my windows 10
Referenced by issue #84519, Solidify generage an abnormal vertex point
Referenced by issue #84360, ERROR EXCEPTION_ACCESS_VIOLATION IN WINDOWS 10 (64BIT)
Referenced by issue #84324, Blender crashes during composited scenes rendering
Referenced by issue #84300, File save is very slow under Big Sur, "Listing Dirs..." for minutes
Referenced by issue #83963, Crashed at first run of the latest released installed from your site
Referenced by issue #83939, Blender randomly stops responding under Linux.
Referenced by issue #83862, Graphics driver issues with Chrome Remote Desktop
Referenced by issue #83762, Blender crashes to do with textures
Referenced by issue #83721, Blender (ISD_Tablet.dll) crashes when you lock Windows 10 Tablet PC.
Referenced by issue #83698, Blender crash at launching
Referenced by issue #83653, Problem with Cycles GPU viewport shading (GTX 1070) both CUDA and optix
Referenced by issue #83613, BLENDER OBJECT GLITCH
Referenced by issue #83487, Viewport rendered shading keeps refreshing
Referenced by issue #83458, Crash on Startup
Referenced by issue #83264, Windows 10 Start Menu Tile Shows Version for Microsoft Store Installations
Referenced by issue #83199, Blender crashes when adding a particle system to a mesh object and switching the type to Hair
Referenced by issue #83202, Right click select is still Left Click select 2.91
Referenced by issue #83124, I am having issues with opening blender
Referenced by issue #83017, Newly loaded Blender 2.91 crashes at launch

source/blender/blenkernel/BKE_blender_version.h

@@ -35,7 +35,7 @@ extern "C" {
 /* Blender patch version for bugfix releases. */
 #define BLENDER_VERSION_PATCH 0
 /** Blender release cycle stage: alpha/beta/rc/release. */
-#define BLENDER_VERSION_CYCLE beta
+#define BLENDER_VERSION_CYCLE release
 
 /* Blender file format version. */
 #define BLENDER_FILE_VERSION BLENDER_VERSION