Add a spinner while validating before publishing (#3776)

diff --git a/lib/src/command/lish.dart b/lib/src/command/lish.dart
index 7ecb30b..53cec88 100644
--- a/lib/src/command/lish.dart
+++ b/lib/src/command/lish.dart
@@ -298,14 +298,17 @@
     final warnings = <String>[];
     final errors = <String>[];
 
-    await Validator.runAll(
-      entrypoint,
-      packageSize,
-      host,
-      files,
-      hints: hints,
-      warnings: warnings,
-      errors: errors,
+    await log.spinner(
+      'Validating package',
+      () async => await Validator.runAll(
+        entrypoint,
+        packageSize,
+        host,
+        files,
+        hints: hints,
+        warnings: warnings,
+        errors: errors,
+      ),
     );
 
     if (errors.isNotEmpty) {
diff --git a/test/testdata/goldens/directory_option_test/commands taking a --directory~-C parameter work.txt b/test/testdata/goldens/directory_option_test/commands taking a --directory~-C parameter work.txt
index bcd8451..5d45f56 100644
--- a/test/testdata/goldens/directory_option_test/commands taking a --directory~-C parameter work.txt
+++ b/test/testdata/goldens/directory_option_test/commands taking a --directory~-C parameter work.txt
@@ -111,6 +111,7 @@
 ├── lib
 │   └── test_pkg.dart (<1 KB)
 └── pubspec.yaml (<1 KB)
+Validating package...
 The server may enforce additional checks.
 [STDERR] 
 [STDERR] Package has 0 warnings.
diff --git a/test/testdata/goldens/lish/many_files_test/displays all files.txt b/test/testdata/goldens/lish/many_files_test/displays all files.txt
index 7171f66..82a9431 100644
--- a/test/testdata/goldens/lish/many_files_test/displays all files.txt
+++ b/test/testdata/goldens/lish/many_files_test/displays all files.txt
@@ -29,6 +29,7 @@
 │   ├── file_9.dart (<1 KB)
 │   └── test_pkg.dart (<1 KB)
 └── pubspec.yaml (<1 KB)
+Validating package...
 
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