Fix CI: Turn off go modules for xgo and gxz (#115)

Turn off go modules for xgo and gxz

as on https://github.com/go-gitea/gitea/pull/10963

Revert "Fix CI: workaround from @kolaente (#113)"

This reverts commit b37673c954.

Co-authored-by: 6543 <6543@obermui.de>
Reviewed-on: https://gitea.com/gitea/tea/pulls/115
Reviewed-by: techknowlogick <techknowlogick@gitea.io>
Reviewed-by: John Olheiser <john.olheiser@gmail.com>

.drone.yml

@@ -74,9 +74,6 @@ steps:
   image: techknowlogick/xgo:latest
   environment:
     GOPROXY: https://goproxy.cn
-    # This path does not exist. However, when we set the gopath to /go, the build fails. Not sure why.
-    # Leaving this here until we know how to resolve this properly.
-    GOPATH: /srv/app
   commands:
   - export PATH=$PATH:$GOPATH/bin
   - make release