Update V8 version to 8.0

TBR=machenbach@chromium.org
CC=hablich@chromium.org

No-Try: true
Change-Id: I19512e953adce96c5d559e4552543fe2c11042d2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1863937Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64353}

include/v8-version.h

@@ -8,8 +8,8 @@
 // These macros define the version number for the current version.
 // NOTE these macros are used by some of the tool scripts and the build
 // system so their names cannot be changed without changing the scripts.
-#define V8_MAJOR_VERSION 7
-#define V8_MINOR_VERSION 9
+#define V8_MAJOR_VERSION 8
+#define V8_MINOR_VERSION 0
 #define V8_BUILD_NUMBER 0
 #define V8_PATCH_LEVEL 0