Update license information in pyproject.toml

Author: claudiodsf

pyproject.toml

@@ -9,11 +9,12 @@ authors = [
     { name = "Claudio Satriano", email = "satriano@ipgp.fr" },
 ]
 description = "Repeating earthquakes search and analysis"
+license = "GPL-3.0-or-later"
+license-files = ["LICENSE.txt"]
 classifiers = [
     "Development Status :: 4 - Beta",
     "Environment :: Console",
     "Intended Audience :: Science/Research",
-    "License :: OSI Approved :: GNU General Public License v3 or later (GPLv3+)",
     "Operating System :: OS Independent",
     "Programming Language :: Python",
     "Programming Language :: Python :: 3",
@@ -37,9 +38,6 @@ dependencies = [
     "pygments",
 ]
 
-[project.license]
-text = "GNU General Public License v3 or later (GPLv3+)"
-
 [project.urls]
 Homepage = "https://requake.seismicsource.org"
 Source = "https://github.com/SeismicSource/requake"