chore: add missing OSS compliance files @W-24528552@

CODEOWNERS

@@ -3,3 +3,5 @@
 
 # Comment line immediately above ownership line is reserved for related other information. Please be careful while editing.
 #ECCN:Open Source
+#GUSINFO:Platform CLI,Platform CLI
+* @salesforcecli/cli

CONTRIBUTING.md

@@ -0,0 +1,32 @@
+## Contributing
+
+1. Please read our [Code of Conduct](CODE_OF_CONDUCT.md).
+1. Please create a new issue [here](https://github.com/forcedotcom/cli/issues) before starting any work so that we can also offer suggestions or let you know if there is already an effort in progress.
+1. Sign the Salesforce [CLA](#cla).
+1. The CLI team will review your pull request and provide feedback.
+1. Once merged, a new release of `@salesforcecli/github-workflows` will be published to [npm](https://www.npmjs.com/package/@salesforcecli/github-workflows).
+
+### CLA
+
+External contributors are required to sign a Contributor License
+Agreement. You can do so by going to https://cla.salesforce.com/sign-cla.
+
+## Branches
+
+- We work in branches off of `main`.
+- Our release (aka. _production_) branch is `main`.
+- Other repos reference `main` directly from this repository.
+- Our work happens in _topic_ branches (feature and/or bug-fix).
+  - Feature as well as bug-fix branches are based on `main`
+  - Branches _should_ be kept up-to-date using `rebase`
+
+## Pull Requests
+
+- Develop features and bug fixes in _topic_ branches off main, or forks.
+- _Topic_ branches can live in forks (external contributors) or within this repository (internal contributors).
+  - When creating _topic_ branches in this repository please prefix with `<initials>/`. For example: `mb/refactor-tests`.
+- Use [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/#summary) to drive semver versioning. Examples:
+  - `chore: my chore message` --> No release
+  - `fix: my fix message` --> Patch release
+  - `feat: my feat message` --> Minor release
+- PRs will be reviewed and merged by the CLI team.