miniupnpc: conflicts_with "wownero"

Add a `conflicts_with` directive to indicate that the newly-added
`wownero` formula [1] also installs a `libminiupnpc.a` library.

This currently blocks CI on PR #59257 [2]. To get this out of the
way quickly, use `conflicts_with` for now instead of making
`miniupnpc` a dependency of `wownero`.

[1]: #59687

[2]: #59257

Closes #60391.

Signed-off-by: Sean Molenaar <1484494+SMillerDev@users.noreply.github.com>
Signed-off-by: BrewTestBot <1589480+BrewTestBot@users.noreply.github.com>

Formula/miniupnpc.rb

@@ -20,6 +20,8 @@ class Miniupnpc < Formula
     sha256 "b65b947374b703c4473c6f4daa74090181c7372e4b2d663a05890f988605eab9" => :el_capitan
   end
 
+  conflicts_with "wownero", because: "wownero ships its own copy of miniupnpc"
+
   def install
     system "make", "INSTALLPREFIX=#{prefix}", "install"
   end