add version matrix

RELEASES.md

@@ -97,6 +97,21 @@ As rule of thumb, the following changes will **NOT** be automatically accepted i
 * **API-breaking changes**, i.e. changes that prevent client applications to *build without modifications* to the client application's source code.
 * **CLI-breaking changes**, i.e. changes that require usage changes for CLI users.
 
+## Version matrix
+
+Versions of Golang, Cosmos SDK and Tendermint used by ibc-go in the currently active releases:
+
+| Go | ibc-go | Cosmos SDK | Tendermint |
+|----|--------|------------|------------|
+| 1.15 | v2.1.0 | v0.44.6 | v0.34.14 |
+| 1.15 | v2.1.1 | v0.44.8 | v0.34.19 |
+| 1.15 | v2.2.0 | v0.45.1 | v0.34.14 |
+| 1.15 | v2.2.1 | v0.45.1 | v0.34.14 |
+| 1.17 | v2.3.0 | v0.45.4 | v0.34.19 |
+| 1.17 | v3.0.0 | v0.45.1 | v0.34.14 |
+| 1.17 | v3.0.1 | v0.45.4 | v0.34.19 |
+| 1.17 | v3.1.0 | v0.45.4 | v0.34.19 |
+
 ## Graphics
 
 The decision tree above was generated with the following code: