Fix the image link and add versioning details

Signed-off-by: Fabio José <[email protected]>

Author: fabiojose

README.md

@@ -6,7 +6,19 @@
 
 Official CloudEvents' SDK for JavaScript.
 
-<img src="https://raw.githubusercontent.com/cncf/artwork/master/cloudevents/horizontal/color/cloudevents-horizontal-color.png" width="300" height="58" alt="CloudEvents logo">
+<img src="https://github.com/cncf/artwork/blob/master/projects/cloudevents/horizontal/color/cloudevents-horizontal-color.png" width="300" height="58" alt="CloudEvents logo">
+
+## Versioning
+
+__Before Spec reaches 1.0__
+
+- `0.x.p`: `x` relates to spec version and `p` relates to fixes or patches, see
+[semver](https://semver.org/)
+
+__After Spec reaches 1.0__
+
+- `x.M.p`: `x` relates to spec version, `M` relates to minor and `p` relates
+to fixes or patches. See [semver](https://semver.org/)
 
 ## Installation