guile-gnutls: Fix livecheck.

Add gitlab group to get working livecheck.

* guile/guile-gnutls/Portfile (gitlab.setup): Call.
(extract.suffix, use_bzip2): Still use .tar.gz.

guile/guile-gnutls/Portfile

@@ -1,6 +1,7 @@
 # -*- coding: utf-8; mode: tcl; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- vim:fenc=utf-8:ft=tcl:et:sw=4:ts=4:sts=4
 
 PortSystem          1.0
+PortGroup           gitlab 1.0
 
 name                guile-gnutls
 categories          guile net security
@@ -13,13 +14,18 @@ checksums           rmd160  4ac751aca5616735001f630951fdd0942d9a73c4 \
                     sha256  5b4cb926032076ec346bb5c0bc0d0231f968fe0f565913cc16934bb793afb239 \
                     size    747952
 
+gitlab.setup        gnutls guile ${version} v
+
 description         Guile bindings for GnuTLS
 long_description    Guile-GnuTLS provides Guile bindings for the GnuTLS library.
 
 distname            ${name}-${version}
 homepage            http://www.gnutls.org/
 master_sites        https://gitlab.com/-/project/40217954/uploads/9060bc55069cedb40ab46cea49b439c0/
 
+extract.suffix      .tar.gz
+use_bzip2           no
+
 depends_lib-append  port:gnutls \
                     port:guile-3.0