overlays: add 'woodpecker-2.0.0-rc.0'

The point was initially to quickly test the release candidate and wait
for the official v2.

Unfortunately I've encountered some issues trying to get the package
working for the official version. So let's just roll with it for now...

overlays/woodpecker-2.0.0-rc.0/server.nix

@@ -0,0 +1,27 @@
+{ buildGoModule, callPackage, 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";
+    mainProgram = "woodpecker-server";
+  };
+}