chore(doc): update compatibility matrix (#2287)

Author: vmarchaud

README.md

@@ -48,7 +48,8 @@ This is the JavaScript version of [OpenTelemetry](https://opentelemetry.io/), a
 
 | API Version | Core version | Contrib Version         |
 | ----------- |--------------|-------------------------|
-| 0.21.x      | 0.21.x       | ------                  |
+| 1.0.0       | ------       | ------                  |
+| 0.21.x      | 0.21.x       | 0.21.x                  |
 | 0.20.x      | 0.20.x       | 0.20.x                  |
 | v1.0.0-rc.3 | 0.19.x       | 0.16.x                  |
 | 0.18.x      | 0.18.x       | 0.14.x                  |