Update readme version link and bump version in changelog/pubspec

pkgs/pubspec_parse/CHANGELOG.md

diff --git a/pkgs/pubspec_parse/CHANGELOG.md b/pkgs/pubspec_parse/CHANGELOG.md
index 5f3d5d6..6b5a04d 100644
--- a/pkgs/pubspec_parse/CHANGELOG.md
+++ b/pkgs/pubspec_parse/CHANGELOG.md
@@ -1,3 +1,5 @@
+## 1.2.1-dev
+
 ## 1.2.0
 
 - Added support for `screenshots` field.

pkgs/pubspec_parse/README.md

diff --git a/pkgs/pubspec_parse/README.md b/pkgs/pubspec_parse/README.md
index ed00eed..eca3610 100644
--- a/pkgs/pubspec_parse/README.md
+++ b/pkgs/pubspec_parse/README.md
@@ -1,5 +1,5 @@
 [![Build Status](https://github.com/dart-lang/pubspec_parse/workflows/Dart%20CI/badge.svg)](https://github.com/dart-lang/pubspec_parse/actions?query=workflow%3A"Dart+CI"+branch%3Amaster)
-[![pub package](https://img.shields.io/pub/v/package_config.svg)](https://pub.dev/packages/pubspec_parse)
+[![pub package](https://img.shields.io/pub/v/pubspec_parse.svg)](https://pub.dev/packages/pubspec_parse)
 
 Supports parsing `pubspec.yaml` files with robust error reporting and support
 for most of the documented features.

pkgs/pubspec_parse/pubspec.yaml

diff --git a/pkgs/pubspec_parse/pubspec.yaml b/pkgs/pubspec_parse/pubspec.yaml
index c2be3dc..3932fd9 100644
--- a/pkgs/pubspec_parse/pubspec.yaml
+++ b/pkgs/pubspec_parse/pubspec.yaml
@@ -2,7 +2,7 @@
 description: >-
   Simple package for parsing pubspec.yaml files with a type-safe API and rich
   error reporting.
-version: 1.2.0
+version: 1.2.1-dev
 repository: https://github.com/dart-lang/pubspec_parse
 
 environment: