Bump version to v1.21.0-dev

BUILD

@@ -74,11 +74,11 @@ config_setting(
 )
 
 # This should be updated along with build.yaml
-g_stands_for = "godric"
+g_stands_for = "gandalf"
 
 core_version = "7.0.0"
 
-version = "1.20.0-dev"
+version = "1.21.0-dev"
 
 GPR_PUBLIC_HDRS = [
     "include/grpc/support/alloc.h",

build.yaml

@@ -13,8 +13,8 @@ settings:
   '#09': Per-language overrides are possible with (eg) ruby_version tag here
   '#10': See the expand_version.py for all the quirks here
   core_version: 7.0.0
-  g_stands_for: godric
-  version: 1.20.0-dev
+  g_stands_for: gandalf
+  version: 1.21.0-dev
 filegroups:
 - name: alts_proto
   headers:

doc/g_stands_for.md

@@ -19,4 +19,5 @@
 - 1.17 'g' stands for ['gizmo'](https://github.com/grpc/grpc/tree/v1.17.x)
 - 1.18 'g' stands for ['goose'](https://github.com/grpc/grpc/tree/v1.18.x)
 - 1.19 'g' stands for ['gold'](https://github.com/grpc/grpc/tree/v1.19.x)
-- 1.20 'g' stands for ['godric'](https://github.com/grpc/grpc/tree/master)
+- 1.20 'g' stands for ['godric'](https://github.com/grpc/grpc/tree/v1.20.x)
+- 1.21 'g' stands for ['gandalf'](https://github.com/grpc/grpc/tree/master)