chore(README): link to Semver 2 spec

README.md

@@ -84,7 +84,7 @@ Differences from Helm Classic:
 - Helm's chart format has changed for the better:
   - Dependencies are immutable and stored inside of a chart's `charts/`
     directory.
-  - Charts are strongly versioned using SemVer 2
+  - Charts are strongly versioned using [SemVer 2](http://semver.org/spec/v2.0.0.html)
   - Charts can be loaded from directories or from chart archive files
   - Helm supports Go templates without requiring you to run `generate`
     or `template` commands.
@@ -99,4 +99,3 @@ Differences from Helm Classic:
   - And you can still load charts from a local directory.
 - The Helm workspace is gone. You can now work anywhere on your
   filesystem that you want to work.
-