Update release notes

Signed-off-by: ela-kotulska-frequenz <[email protected]>

Author: ela-kotulska-frequenz

RELEASE_NOTES.md

@@ -2,17 +2,26 @@
 
 ## Summary
 
-<!-- Here goes a general summary of what this release is about -->
-
 ## Upgrading
 
-<!-- Here goes notes on how to upgrade from previous versions, including deprecations and what they should be replaced with --> 
-
 ## New Features
 
+- Upgrade PowerDistributingActor to track if batteries are working
+  https://github.com/frequenz-floss/frequenz-sdk-python/pull/117
+
+- Simplify `Resampler` by moving configuration to its own class `ResamplerConfig`
+  https://github.com/frequenz-floss/frequenz-sdk-python/pull/131
+
+- Add `initial_buffer_len` to the ResamplerConfig. This means that `Resampler` will store at least this number of arguments. Other `Resampler` behaviour won't change
+  https://github.com/frequenz-floss/frequenz-sdk-python/pull/131
+
 - Ability to compose formula outputs into higher-order formulas:
   https://github.com/frequenz-floss/frequenz-sdk-python/pull/133
 
+- Add a formula generator for SoC in the LogicalMeter
+  https://github.com/frequenz-floss/frequenz-sdk-python/pull/137
+
+
 ## Bug Fixes
 
 - Formulas with repeated operators like `#1 - #2 - #3` were getting