[PATCH] tuna: Fix setuptools deprecation warnings for license field

Update pyproject.toml to use modern SPDX license expression format
and remove deprecated license classifier. The license field now uses
a simple string "GPL-2.0-only" instead of the deprecated {text = "..."}
format, and the redundant license classifier has been removed from the
classifiers list.

Also add missing SPDX-License-Identifier header to tuna/help.py to
ensure all source files have proper license identification.

These changes eliminate setuptools deprecation warnings about license
field format and license classifiers when building the package, while
maintaining the same GPL-2.0-only license.

Assisted-by: Claude Sonnet 4.5 <[email protected]>
Signed-off-by: John Kacur <[email protected]>
---
 pyproject.toml | 3 +--
 tuna/help.py   | 1 +
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/pyproject.toml b/pyproject.toml
index f0caac6df053..ca149c352df0 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ build-backend = "setuptools.build_meta"
 name = "tuna"
 version = "0.20"
 description = "Application tuning GUI"
-license = {text = "GPL-2.0-only"}
+license = "GPL-2.0-only"
 authors = [
     {name = "Arnaldo Carvalho de Melo", email = "[email protected]"},
     {name = "John Kacur", email = "[email protected]"}
@@ -21,7 +21,6 @@ dependencies = [
 classifiers = [
     "Development Status :: 4 - Beta",
     "Intended Audience :: System Administrators",
-    "License :: OSI Approved :: GNU General Public License v2 (GPLv2)",
     "Operating System :: POSIX :: Linux",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3.10",
diff --git a/tuna/help.py b/tuna/help.py
index db8b4c84df63..1a9473a86875 100644
--- a/tuna/help.py
+++ b/tuna/help.py
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 
 import gettext
 _ = gettext.gettext
-- 
2.54.0