[url_launcher] Major version bump for desktop Dart-based url_launcher implementations (#4777)

https://github.com/flutter/plugins/pull/4719 converted the url_launcher implementations to Dart-based versions. This should have been completely transparent to clients, but there is a latent bug in `url_launcher` where the `default_package` entries for Linux, macOS, and Windows are incorrect. This went unnoticed until now because currently the only client-facing effect of `default_package` is in resolving which implementation to run Dart registration for. Because of the typos in the `default_package` entries, the resolution in the `flutter` tool doesn't recognize the registration for these packages as needing to run, causing them to be broken at runtime.

The affected versions have been retracted to fix the breakage in the short term. This is PR is the first half of the long-term fix; it re-releases them as a major version bump so that existing versions of `url_launcher` will not pick them up. Once they are published, a follow-up PR will update `url_launcher` to fix the typos and relax the version constraints for the dependencies on these implementation packages to allow 2.x or 3.x. (In theory this could be one PR, but doing it as two ensures that we get real testing on the `url_launcher` change, so is safer.)

Part of a long-term fix for https://github.com/flutter/flutter/issues/98097
diff --git a/packages/url_launcher/url_launcher_linux/CHANGELOG.md b/packages/url_launcher/url_launcher_linux/CHANGELOG.md
index f346094..0fc373f 100644
--- a/packages/url_launcher/url_launcher_linux/CHANGELOG.md
+++ b/packages/url_launcher/url_launcher_linux/CHANGELOG.md
@@ -1,6 +1,13 @@
+## 3.0.0
+
+* Changes the major version since, due to a typo in `default_package` in
+  existing versions of `url_launcher`, requiring Dart registration in this
+  package is in practice a breaking change.
+  * Does not include any API changes; clients can allow both 2.x or 3.x.
+
 ## 2.0.4
 
-* Switches to an in-package method channel implementation.
+* **\[Retracted\]** Switches to an in-package method channel implementation.
 
 ## 2.0.3
 
diff --git a/packages/url_launcher/url_launcher_linux/pubspec.yaml b/packages/url_launcher/url_launcher_linux/pubspec.yaml
index ee55920..cb9a0be 100644
--- a/packages/url_launcher/url_launcher_linux/pubspec.yaml
+++ b/packages/url_launcher/url_launcher_linux/pubspec.yaml
@@ -2,7 +2,7 @@
 description: Linux implementation of the url_launcher plugin.
 repository: https://github.com/flutter/plugins/tree/main/packages/url_launcher/url_launcher_linux
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+url_launcher%22
-version: 2.0.4
+version: 3.0.0
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
diff --git a/packages/url_launcher/url_launcher_macos/CHANGELOG.md b/packages/url_launcher/url_launcher_macos/CHANGELOG.md
index 2bf9de9..082bc45 100644
--- a/packages/url_launcher/url_launcher_macos/CHANGELOG.md
+++ b/packages/url_launcher/url_launcher_macos/CHANGELOG.md
@@ -1,6 +1,13 @@
+## 3.0.0
+
+* Changes the major version since, due to a typo in `default_package` in
+  existing versions of `url_launcher`, requiring Dart registration in this
+  package is in practice a breaking change.
+  * Does not include any API changes; clients can allow both 2.x or 3.x.
+
 ## 2.0.4
 
-* Switches to an in-package method channel implementation.
+* **\[Retracted\]** Switches to an in-package method channel implementation.
 
 ## 2.0.3
 
diff --git a/packages/url_launcher/url_launcher_macos/pubspec.yaml b/packages/url_launcher/url_launcher_macos/pubspec.yaml
index 0cd25d2..8b5183b 100644
--- a/packages/url_launcher/url_launcher_macos/pubspec.yaml
+++ b/packages/url_launcher/url_launcher_macos/pubspec.yaml
@@ -2,7 +2,7 @@
 description: macOS implementation of the url_launcher plugin.
 repository: https://github.com/flutter/plugins/tree/main/packages/url_launcher/url_launcher_macos
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+url_launcher%22
-version: 2.0.4
+version: 3.0.0
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
diff --git a/packages/url_launcher/url_launcher_windows/CHANGELOG.md b/packages/url_launcher/url_launcher_windows/CHANGELOG.md
index a562da1..e02f5a2 100644
--- a/packages/url_launcher/url_launcher_windows/CHANGELOG.md
+++ b/packages/url_launcher/url_launcher_windows/CHANGELOG.md
@@ -1,5 +1,14 @@
+## 3.0.0
+
+* Changes the major version since, due to a typo in `default_package` in
+  existing versions of `url_launcher`, requiring Dart registration in this
+  package is in practice a breaking change.
+  * Does not include any API changes; clients can allow both 2.x or 3.x.
+
 ## 2.0.3
 
+**\[Retracted\]**
+
 * Switches to an in-package method channel implementation.
 * Adds unit tests.
 * Updates code for new analysis options.
diff --git a/packages/url_launcher/url_launcher_windows/pubspec.yaml b/packages/url_launcher/url_launcher_windows/pubspec.yaml
index 506e995..95f17ad 100644
--- a/packages/url_launcher/url_launcher_windows/pubspec.yaml
+++ b/packages/url_launcher/url_launcher_windows/pubspec.yaml
@@ -2,7 +2,7 @@
 description: Windows implementation of the url_launcher plugin.
 repository: https://github.com/flutter/plugins/tree/main/packages/url_launcher/url_launcher_windows
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+url_launcher%22
-version: 2.0.3
+version: 3.0.0
 
 environment:
   sdk: ">=2.12.0 <3.0.0"