Fix MR Selection, Go Code Refactor (#358)

refactor: Refactors the Go codebase into a more modular and idiomatic approach
fix: require selection of specific MR when there are multiple targets for a given source branch
feat: Allows for the passing of Gitlab's filter options when choosing an MR, improves MR selection
feat: API to choose an MR from a list based on the provided username's involvement as an assignee/reviewer/author

This is a #MINOR release

.github/CONTRIBUTING.md

@@ -38,11 +38,10 @@ $ go fmt ./...
 $ golangci-lint run
 ```
 
-If you are writing tests and have added something to the Go client, you can re-generate the mocked client like so:
+If you are writing tests and have added something to the Go client, you can test with:
 
 ```bash
-$ go install go.uber.org/mock/mockgen@latest # Install the mockgen CLI on your machine
-$ mockgen -source cmd/types.go > cmd/mocks/fake_client.go
+$ make test
 ```
 
 For changes to the Lua codebase: We use <a href="https://github.com/JohnnyMorganz/StyLua">stylua</a> for formatting and <a href="https://github.com/mpeterv/luacheck">luacheck</a> for linting. Run these commands in the root of the repository:

.github/workflows/go.yaml

@@ -19,6 +19,7 @@ jobs:
         with:
           version: v1.54
           only-new-issues: true
+          skip-cache: true
   go_test:
     name: Test Go 🧪 
     needs: [go_lint]