asdf: update to 0.18.1

sysutils/asdf/Portfile

@@ -3,7 +3,7 @@
 PortSystem          1.0
 PortGroup           golang 1.0
 
-go.setup            github.com/asdf-vm/asdf 0.18.0 v
+go.setup            github.com/asdf-vm/asdf 0.18.1 v
 go.offline_build    no
 revision            0
 
@@ -21,9 +21,9 @@ long_description    ${name} is a CLI tool that can manage multiple language \
                     runtime versions on a per-project basis.
 homepage            https://asdf-vm.com/
 
-checksums           rmd160  d247ba64e93c533883ac539991a4fa487971832d \
-                    sha256  c452a886503277260b7c82c07031800340f892bb2147bb3af67dca7268a410b5 \
-                    size    328965
+checksums           rmd160  8713cdc79f32e7fe62abc43d25ed875a487fc0a8 \
+                    sha256  3dbde020f345d397f4cf1eb1fceabba552ea3aaf83108785b1a9e9a1d6430f18 \
+                    size    341917
 
 build.args          -ldflags '-s -w -X main.Version=${github.tag_prefix}${version}' \
                     ./cmd/asdf