Prepare to release cronet_http 1.8.0 (#1881)

pkgs/cronet_http/CHANGELOG.md

diff --git a/pkgs/cronet_http/CHANGELOG.md b/pkgs/cronet_http/CHANGELOG.md
index aa525e7..8ce9872 100644
--- a/pkgs/cronet_http/CHANGELOG.md
+++ b/pkgs/cronet_http/CHANGELOG.md
@@ -1,4 +1,4 @@
-## 1.8.0-wip
+## 1.8.0
 
 * Made callbacks asynchronous to prevent background errors caused by the
   unavailability of the Dart callback.

pkgs/cronet_http/pubspec.yaml

diff --git a/pkgs/cronet_http/pubspec.yaml b/pkgs/cronet_http/pubspec.yaml
index 074d26b..b6e6782 100644
--- a/pkgs/cronet_http/pubspec.yaml
+++ b/pkgs/cronet_http/pubspec.yaml
@@ -1,5 +1,5 @@
 name: cronet_http
-version: 1.8.0-wip
+version: 1.8.0
 description: >-
   An Android Flutter plugin that provides access to the Cronet HTTP client.
 repository: https://github.com/dart-lang/http/tree/master/pkgs/cronet_http