feat(schema): Added schema for process-compose. [debug-based]

[niksingh710]

• Fully depended on debug flag of flake-parts.

To test make sure that the debug flag is true in a flake-parts flake.

e.g on juspay/services-flakes/example/llm apply patch

diff --git a/example/llm/flake.nix b/example/llm/flake.nix
index c7ce558..a5cc377 100644
--- a/example/llm/flake.nix
+++ b/example/llm/flake.nix
@@ -8,6 +8,7 @@
     services-flake.url = "github:juspay/services-flake";
   };
   outputs = inputs: inputs.flake-parts.lib.mkFlake { inherit inputs; } {
+    debug = true;
     systems = import inputs.systems;
     imports = [
       inputs.process-compose-flake.flakeModule

[niksingh710]

Currently, the validity of a process is determined only by checking whether it contains a package and settings attribute.

[srid]

This PR doesn't work for me (on services-flake/examples/llm) with debug flag enabled.

Discussion: https://nixos.zulipchat.com/#narrow/channel/415454-omnix/topic/process-compose.20in.20.60om.20show.60