README.md: add news for next release

Change-Id: I53c2568728cf045bd30a7f501fd51143ecdc4d8e
Reviewed-on: https://code-review.googlesource.com/25691
Reviewed-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Ramon Nogueira <rmn@google.com>
diff --git a/README.md b/README.md
index 80a605f..17d9d3e 100644
--- a/README.md
+++ b/README.md
@@ -33,6 +33,31 @@
 
 ## News
 
+_March 22, 2018_
+
+*v0.20.*
+
+- bigquery: Support SchemaUpdateOptions for load jobs.
+
+- bigtable:
+  - Add SampleRowKeys.
+  - cbt: Support union, intersection GCPolicy.
+  - Retry admin RPCS.
+  - Add trace spans to retries.
+  
+- datastore: Add OpenCensus tracing.
+
+- firestore:
+  - Fix queries involving Null and NaN.
+  - Allow Timestamp protobuffers for time values.
+
+- logging: Add a WriteTimeout option.
+
+- spanner: Support Batch API.
+
+- storage: Add OpenCensus tracing.
+  
+
 _February 26, 2018_
 
 *v0.19.0*