Write a contributing.md for Osmosis

[ValarDragon]

We should write a contributing.md for Osmosis that explains the branching structure, how we use the SDK fork, and how to make / test updates to SDK branches. I've recently explained it 1-1 a couple times, and folks have been left on their own to self-discover what we're doing. Would be ideal to document this.

Things to include:

• How to update dependencies for builds: Better document our process for profiling our code #456 (comment)
• How to change things in vendor for local builds / local testing
• Branch structure of releases on v7, v6, v4, and using the mergify labels for backporting.
• How to build proto files. (rm -rf vendor/ && make build-reproducible once docker is installed)

[faddat]

@ValarDragon why use make build-reproducible when building proto files?

I've always used make proto-gen -- is make build-reproducible preferable somehow?

[ValarDragon]

nope it should've been make proto-all, I just typed the wrong thing haha

[jlbit]

+1, I'm a newbie trying to contribute to osmosis (also not so familiar with golang) but hardly find any docs to website. Having really a hard time to get started. Something like https://nightlies.apache.org/flink/flink-docs-release-1.14/docs/flinkdev/building/ should be extremely helpful

@ValarDragon any update/progress on this? Happy to partner with you and write this up as I ramp up

[xBalbinus]

#1399 Adding this as a place to track work on this issue

[xBalbinus]

Closing, as #1399 has been merged.