pumba: remove gopath

Closes #48176.

Signed-off-by: Rui Chen <chenrui333@gmail.com>

Formula/pumba.rb

@@ -15,16 +15,10 @@ class Pumba < Formula
   depends_on "go" => :build
 
   def install
-    ENV["GOPATH"] = buildpath
-
-    src = buildpath/"src/github.com/alexei-led/pumba"
-    src.install buildpath.children
-    src.cd do
-      system "go", "build", "-o", bin/"pumba", "-ldflags",
-             "-X main.Version=#{version}", "./cmd"
+    system "go", "build", "-ldflags", "-s -w -X main.Version=#{version}",
+           "-trimpath", "-o", bin/"pumba", "./cmd"
     prefix.install_metafiles
   end
-  end
 
   test do
     output = pipe_output("#{bin}/pumba rm test-container 2>&1")