13.4: update stable/13 to -PRERELEASE

This marks the start of the FreeBSD 13.4 release cycle; the stable/13
tree is now in "code slush".

Developers are encouraged to prioritize fixing bugs (and/or merging bug
fixes from HEAD) over new features at this time.  Commit approval from
re@ is not required but if new features introduce problems they may be
removed from the release.

Approved by:	re (implicit)
Sponsored by:	Amazon

sys/conf/newvers.sh

@@ -52,8 +52,8 @@
 #
 
 TYPE="FreeBSD"
-REVISION="13.3"
-BRANCH="STABLE"
+REVISION="13.4"
+BRANCH="PRERELEASE"
 if [ -n "${BRANCH_OVERRIDE}" ]; then
 	BRANCH=${BRANCH_OVERRIDE}
 fi

usr.bin/yacc/config.h

@@ -86,7 +86,7 @@
 #define STDC_HEADERS 1
 
 /* Define to the system name. */
-#define SYSTEM_NAME "freebsd13.3"
+#define SYSTEM_NAME "freebsd13.4"
 
 /* "Define to 1 if you want to use dbmalloc for testing." */
 /* #undef USE_DBMALLOC */