.github/workflows/build.yml: disable NFS support

Homebrew comes with libnfs 6 which is not supported by MPD 0.23.

Author: MaxKellermann

.github/workflows/build.yml

@@ -122,7 +122,6 @@ jobs:
             googletest \
             icu4c \
             ffmpeg \
-            libnfs \
             yajl \
             libupnp \
             libid3tag \