Bump N+ version to 21.

alpine/Makefile

diff --git a/alpine/Makefile b/alpine/Makefile
index 888e5da..780db6c 100644
--- a/alpine/Makefile
+++ b/alpine/Makefile
@@ -2,7 +2,7 @@
 
 BASE_VERSION=	1.17.9
 BASE_RELEASE=	1
-PLUS_VERSION=	20
+PLUS_VERSION=	21
 PLUS_RELEASE=	${BASE_RELEASE}
 BASE_SRC=	nginx-$(BASE_VERSION).tar.gz
 SRCDIR=		nginx-$(BASE_VERSION)

debian/Makefile

diff --git a/debian/Makefile b/debian/Makefile
index 33f5a31..06660f6 100644
--- a/debian/Makefile
+++ b/debian/Makefile
@@ -2,7 +2,7 @@
 
 BASE_VERSION=	1.17.9
 BASE_RELEASE=	1
-PLUS_VERSION=	20
+PLUS_VERSION=	21
 BASE_SRC=	nginx-$(BASE_VERSION).tar.gz
 SRCDIR=		nginx-$(BASE_VERSION)
 SRCPATH?=	../..

rpm/SPECS/Makefile

diff --git a/rpm/SPECS/Makefile b/rpm/SPECS/Makefile
index 13632f2..bfadf2e 100644
--- a/rpm/SPECS/Makefile
+++ b/rpm/SPECS/Makefile
@@ -2,7 +2,7 @@
 
 BASE_VERSION=	1.17.9
 BASE_RELEASE=	1
-PLUS_VERSION=	20
+PLUS_VERSION=	21
 BASE_SRC=	nginx-$(BASE_VERSION).tar.gz
 SRCPATH?=	../SOURCES
 BUILD_ENV_PATH=	${HOME}/rpmbuild