docs: Add section about prefered dependency version strategy

Author: achingbrain

js-code-guidelines.md

@@ -19,6 +19,7 @@ Our toolkit for each of these is not set in stone, and we don't plan to halt our
 - [Contributing](#contributing)
   - [Guidelines](#guidelines)
     - [Linting & Code Style](#linting--code-style)
+    - [Dependency Versions](#dependency-versions)
     - [Testing](#testing)
     - [Releasing](#releasing)
     - [Documentation](#documentation)
@@ -136,6 +137,10 @@ However, we've added an extra linting rule: Enforce the use of [strict mode](htt
 
 Using [aegir-lint](#aegir) will help you do this easily; it automatically lints your code.
 
+#### Dependency Versions
+
+Our rule is: Use ~ for everything below 1.0.0 and ^ for everything above 1.0.0. If you find a package.json that is not following this rule, please submit a PR.
+
 #### Testing
 
 Since `js-ipfs` is meant to be both a Node.js and Browser app, we strongly recommend having tests that run in both platforms, always. For most cases, we use [mocha](http://mochajs.org) to run write the tests and [karma](http://karma-runner.github.io) to automate the test execution in the browser. This solution has been extremely convenient.