shadow: Update to version 4.18.0

shadow: Update to version 4.18.0

- Update from version 4.17.4 to 4.18.0
- Update of rootfile not required
- Changelog
    4.18.0
	    CI: purge man-db by @ikerexxe in #1241
	    passwd: document exit code when PAM has errored by @hallyn in #1244
	    Man patches by @zeha in #1175
	    Quick fix: define E_PAM_ERR in lib/pam_pass.c by @hallyn in #1245
	    Accept /usr/sbin/nologin as an alternate to /sbin/nologin by @zeha in #1246
	    Add LOGIN_ENV_SAFELIST to FOREIGNDEFS by @stanislav-brabec in #1248
	    ci: add gawk as a fedora dependency by @ikerexxe in #1252
	    man/useradd.8.xml: fix the CREATE_HOME description by @hallyn in #1251
	    lib/getdate.y: Restrict the date formats that we support by
	     @alejandro-colomar in #1238
	    newuidmap: better error logging on failure by @matthewhughes934 in #1254
	    Extend basic test cases to check shadow and gshadow entries by
	     @ikerexxe in #1237
	    lib/sizeof.h: Make sure STRLEN() only accepts string literals by
	     @alejandro-colomar in #1260
	    Add strprefix(), and use it instead of its pattern by @alejandro-colomar
	     in #1152
	    src/: Simplify, using strpbrk(3) by @alejandro-colomar in #1167
	    lib/string/strdup/: STRNDUPA(): Reimplement in terms of strndupa(3) by
	     @alejandro-colomar in #1189
	    Remove dead beef by @alejandro-colomar in #1230
	    lib/atoi/a2i/: Simplify these macros by calling a2i() by
	     @alejandro-colomar in #1137
	    strtolower(): Add API, and use it instead of its pattern by
	     @alejandro-colomar in #1211
	    lib/: sget*ent(): Simplify by calling strdup(3) by
	     @alejandro-colomar in #1146
	    fields by @alejandro-colomar in #1150
	    yacc(1) is a dead language; bury it deep in the ground by
	     @alejandro-colomar in #1217
	    Test expiration date by @ikerexxe in #1233
	    [scp] Add strcaseprefix(), and use it instead of its pattern by
	     @alejandro-colomar in #1262
	    valid_field(): Improve readability by @alejandro-colomar in #1208
	    lib/, src/, tests/: Use the standard countof() instead of our NITEMS() by
	     @alejandro-colomar in #1259
	    lib/fs/mkstemp/, src/: Move fmkomstemp() to separate files under
	     lib/fs/mkstemp/, and split into mkomstemp() by @alejandro-colomar in #1139
	    [x][v]aprintf(): Add APIs, and use them instead of [x][v]asprintf(3) by
	     @alejandro-colomar in #1168
	    lib/get_pid.c: pid_t is a signed integer by @alejandro-colomar in #1264
	    src/newusers.c: Fix off-by-one benign bug in array declaration by
	     @alejandro-colomar in #1266
	    Add some wrappers for usual loops around strsep(3) by @alejandro-colomar
	     in #1155
	    lib/fs/readlink/areadlink.h: areadlink(): Avoid inconditionally using
	     PATH_MAX by @sthibaul in #1222
	    configure: Fix typo by @sthibaul in #1268
	    Pre-release 4.18.0-rc1 by @hallyn in #1270
	    Update man pages for chage, shadow, passwd by @domiborges in #1243
	    contrib/: Burn it all by @alejandro-colomar in #1274

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>