Add CONTRIBUTING template

Author: vmwghbot

CONTRIBUTING.md

@@ -0,0 +1,76 @@
+# Contributing to apps-cli-plugin
+
+The apps-cli-plugin project team welcomes contributions from the community. Before you start working with apps-cli-plugin, please
+read our [Developer Certificate of Origin](https://cla.vmware.com/dco). All contributions to this repository must be
+signed as described on that page. Your signature certifies that you wrote the patch or have the right to pass it on
+as an open-source patch.
+
+## Contribution Flow
+
+This is a rough outline of what a contributor's workflow looks like:
+
+- Create a topic branch from where you want to base your work
+- Make commits of logical units
+- Make sure your commit messages are in the proper format (see below)
+- Push your changes to a topic branch in your fork of the repository
+- Submit a pull request
+
+Example:
+
+``` shell
+git remote add upstream https://github.com/vmware-tanzu/apps-cli-plugin.git
+git checkout -b my-new-feature main
+git commit -a
+git push origin my-new-feature
+```
+
+### Staying In Sync With Upstream
+
+When your branch gets out of sync with the vmware-tanzu/main branch, use the following to update:
+
+``` shell
+git checkout my-new-feature
+git fetch -a
+git pull --rebase upstream main
+git push --force-with-lease origin my-new-feature
+```
+
+### Updating pull requests
+
+If your PR fails to pass CI or needs changes based on code review, you'll most likely want to squash these changes into
+existing commits.
+
+If your pull request contains a single commit or your changes are related to the most recent commit, you can simply
+amend the commit.
+
+``` shell
+git add .
+git commit --amend
+git push --force-with-lease origin my-new-feature
+```
+
+If you need to squash changes into an earlier commit, you can use:
+
+``` shell
+git add .
+git commit --fixup <commit>
+git rebase -i --autosquash main
+git push --force-with-lease origin my-new-feature
+```
+
+Be sure to add a comment to the PR indicating your new changes are ready to review, as GitHub does not generate a
+notification when you git push.
+
+### Code Style
+
+### Formatting Commit Messages
+
+We follow the conventions on [How to Write a Git Commit Message](http://chris.beams.io/posts/git-commit/).
+
+Be sure to include any related GitHub issue references in the commit message.  See
+[GFM syntax](https://guides.github.com/features/mastering-markdown/#GitHub-flavored-markdown) for referencing issues
+and commits.
+
+## Reporting Bugs and Creating Issues
+
+When opening a new issue, try to roughly follow the commit message format conventions above.