Merge pull request swiftlang#68 from swiftlang/parispittman-patch-3

Update README.md

README.md

@@ -57,3 +57,19 @@ command-line tool that validates package collections against the defined format.
 
 [`package-collection-diff`](Sources/PackageCollectionDiff/README.md) is a Swift
 command-line tool that compares two package collections to determine if they are different from each other.
+
+## Contributing to Swift Package Collection Generator 
+
+Contributions to this repo are welcomed and encouraged! Please see the
+[Contributing to Swift guide](https://swift.org/contributing/).
+
+To be a truly great community, [Swift.org](https://swift.org/) needs to welcome
+developers from all walks of life, with different backgrounds, and with a wide
+range of experience. A diverse and friendly community will have more great
+ideas, more unique perspectives, and produce more great code. We will work
+diligently to make the Swift community welcoming to everyone.
+
+To give clarity of what is expected of our members, Swift has adopted the
+code of conduct defined by the Contributor Covenant. This document is used
+across many open source communities, and we think it articulates our values
+well. For more, see the [Code of Conduct](https://swift.org/code-of-conduct/).