go.mod: update module dependencies

Author: creachadair

go.mod

@@ -4,7 +4,7 @@ go 1.25.0
 
 require github.com/google/go-cmp v0.7.0
 
-require github.com/creachadair/mds v0.27.1
+require github.com/creachadair/mds v0.28.0
 
 // Bug in flag parsing on nested subcommands.
 retract v0.2.3

go.sum

@@ -1,4 +1,4 @@
-github.com/creachadair/mds v0.27.1 h1:GlO1tPbrsaoafkF6mz7dFutkGXAtIfQLI450u0ypqwA=
-github.com/creachadair/mds v0.27.1/go.mod h1:dMBTCSy3iS3dwh4Rb1zxeZz2d7K8+N24GCTsayWtQRI=
+github.com/creachadair/mds v0.28.0 h1:VS4JsBSlClsqBrHT8cYMTMqFHJdU0P/Z1ES6zjnSMXo=
+github.com/creachadair/mds v0.28.0/go.mod h1:dMBTCSy3iS3dwh4Rb1zxeZz2d7K8+N24GCTsayWtQRI=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=