pkgs: add woodpecker

This is just the same version as upstream, but following the `next`
version.

pkgs/woodpecker/server.nix

@@ -0,0 +1,26 @@
+{ lib, buildGoModule, callPackage, fetchFromGitHub, woodpecker-frontend }:
+let
+  common = callPackage ./common.nix { };
+in
+buildGoModule {
+  pname = "woodpecker-server";
+  inherit (common) version src ldflags postInstall vendorHash;
+
+  postPatch = ''
+    cp -r ${woodpecker-frontend} web/dist
+  '';
+
+  subPackages = "cmd/server";
+
+  CGO_ENABLED = 1;
+
+  passthru = {
+    inherit woodpecker-frontend;
+
+    updateScript = ./update.sh;
+  };
+
+  meta = common.meta // {
+    description = "Woodpecker Continuous Integration server";
+  };
+}