Merge pull request #141 from bank-vaults/version-compatibilits

docs: add version compatibility matrix

README.md

@@ -10,6 +10,17 @@
 
 The official documentation for the operator is available at [https://bank-vaults.dev](https://bank-vaults.dev/docs/operator/).
 
+## Version compatibility matrix
+
+| Operator | Bank-Vaults CLI | Vault[^1]                            |
+|----------|-----------------|--------------------------------------|
+| 1.21.x   | >= 1.20.3       | 1.11.x<br>1.12.x<br>1.13.x<br>1.14.x |
+| 1.20.x   | >= 1.19.0       | 1.10.x<br>1.11.x<br>1.12.x<br>1.13.x |
+
+We provide patches and security fixes for the last two minor versions.
+
+[^1]: The versions listed here are those with which the operator was tested. Newer versions may also be compatible.
+
 ## Development
 
 **For an optimal developer experience, it is recommended to install [Nix](https://nixos.org/download.html) and [direnv](https://direnv.net/docs/installation.html).**