Don't be conservative in upgrade --major-versions without specific pa… (#3539)

lib/src/command/upgrade.dart

diff --git a/lib/src/command/upgrade.dart b/lib/src/command/upgrade.dart
index 25feb70..a83d129 100644
--- a/lib/src/command/upgrade.dart
+++ b/lib/src/command/upgrade.dart
@@ -222,6 +222,14 @@
     }
     final newPubspecText = _updatePubspec(changes);
 
+    // When doing '--majorVersions' for specific packages we try to update other
+    // packages as little as possible to make a focused change (SolveType.get).
+    //
+    // But without a specific package we want to get as many non-major updates
+    // as possible (SolveType.upgrade).
+    final solveType =
+        argResults.rest.isEmpty ? SolveType.upgrade : SolveType.get;
+
     if (_dryRun) {
       // Even if it is a dry run, run `acquireDependencies` so that the user
       // gets a report on changes.
@@ -233,7 +241,7 @@
         lockFile: entrypoint.lockFile,
         solveResult: solveResult,
       ).acquireDependencies(
-        SolveType.get,
+        solveType,
         dryRun: true,
         precompile: _precompile,
         analytics: null, // No analytics for dry-run
@@ -246,7 +254,7 @@
       //       we can show the changes when not in --dry-run mode. For now we only show
       //       the changes made to pubspec.yaml in dry-run mode.
       await Entrypoint(directory, cache).acquireDependencies(
-        SolveType.get,
+        solveType,
         precompile: _precompile,
         analytics: analytics,
       );

test/testdata/goldens/upgrade/example_warns_about_major_versions_test/pub upgrade --major-versions does not update major versions in example~.txt

diff --git a/test/testdata/goldens/upgrade/example_warns_about_major_versions_test/pub upgrade --major-versions does not update major versions in example~.txt b/test/testdata/goldens/upgrade/example_warns_about_major_versions_test/pub upgrade --major-versions does not update major versions in example~.txt
index ae304ea..2cc96c0 100644
--- a/test/testdata/goldens/upgrade/example_warns_about_major_versions_test/pub upgrade --major-versions does not update major versions in example~.txt
+++ b/test/testdata/goldens/upgrade/example_warns_about_major_versions_test/pub upgrade --major-versions does not update major versions in example~.txt
@@ -17,7 +17,9 @@
 ## Section 1
 $ pub upgrade --major-versions --directory example
 Resolving dependencies in example...
+  bar 2.0.0
 > foo 2.0.0 (was 1.0.0)
+  myapp 0.0.0 from path .
 Changed 1 dependency in example!
 
 Changed 1 constraint in pubspec.yaml: