doc: release notes for 1.2.0 (#6)

Signed-off-by: Jaime Silvela <[email protected]>

Author: jsilvela

ReleaseNotes.md

@@ -6,6 +6,24 @@ For a complete list of changes, please refer to the
 [commits](https://github.com/cloudnative-pg/ciclops/commits/main)
 on the `main` branch in GitHub.
 
+## Version 1.2.0
+
+**Release date:** April 28, 2023
+
+Improvements:
+
+- Leverage the GitHub env variables inside the Python code to simplify (#5)
+- General improvements on tests and documentation (#5)
+- Optionally create a short summary for cases where the full summary might
+  exceed the allowed size in GitHub Actions (#4)
+- Compute a new Alerts section with systematic failures, offer standalone for
+  chatops integration (#4)
+- Add unit tests (#4)
+
+Fixes:
+
+- Stop showing `ignoreFail` cases in the code errors table (#4)
+
 ## Version 1.1.0
 
 **Release date:** Feb 20, 2023