Prepare CHANGELOG for v1.2.2 release (spiffe#2925)

Signed-off-by: Ryan Turner <[email protected]>

CHANGELOG.md

@@ -1,5 +1,19 @@
 # Changelog
 
+## [1.2.2] - 2022-04-07
+
+### Added
+- SPIRE Server and Agent log files can be rotated by sending the `SIGUSR2` signal to the process (#2703)
+- K8s Workload Registrar CRD mode now supports registering "downstream" workloads (#2885)
+- SPIRE can now be compiled on macOS machines with an Apple Silicon CPU (#2876)
+- Small documentation improvements (#2851)
+
+### Changed
+- SPIRE Server no longer sets the `DigitalSignature` KeyUsage bit in its CA certificate (#2896)
+
+### Fixed
+- The `k8sbundle` Notifier plugin in SPIRE Server no longer consumes excessive CPU cycles (#2857)
+
 ## [1.2.1] - 2022-03-16
 
 ### Added