caddy: use source downloaded by brew

bayandin · BrewTestBot · commit 431abedb28d9 · 2020-08-23T13:12:39.000Z
Closes Homebrew#60060. Signed-off-by: chenrui <chenrui333@gmail.com> Signed-off-by: BrewTestBot <1589480+BrewTestBot@users.noreply.github.com>
diff --git a/Formula/caddy.rb b/Formula/caddy.rb
@@ -25,7 +25,9 @@ def install
     revision = build.head? ? version.commit : "v#{version}"
 
     resource("xcaddy").stage do
-      system "go", "run", "cmd/xcaddy/main.go", "build", revision, "--output", bin/"caddy"
+      system "go", "run", "cmd/xcaddy/main.go", "build", revision,
+                                                "--with", "github.com/caddyserver/caddy/v2=#{buildpath}",
+                                                "--output", bin/"caddy"
     end
   end
 
