Change license.file to license-files + SPDX-compliance (#528)

I encountered this issue when making a release
astro-informatics/sleplet#451. Also, make
`BSD-3` SPDX-compliant.

---------

Co-authored-by: Matt Graham <[email protected]>

Author: paddyroddy

cookiecutter.json

@@ -11,7 +11,7 @@
   "github_owner": "{{cookiecutter.author_given_names.lower().replace(' ', '-')}}-{{cookiecutter.author_family_names.lower().replace(' ', '-')}}",
   "min_python_version": ["3.11", "3.12", "3.13"],
   "max_python_version": ["3.13", "3.12", "3.11"],
-  "license": ["MIT", "BSD-3", "GPL-3.0"],
+  "license": ["MIT", "BSD-3-Clause", "GPL-3.0"],
   "funder": "",
   "__repo_name": "{{cookiecutter.github_owner}}/{{cookiecutter.project_slug}}",
   "__repo_url": "https://github.com/{{cookiecutter.__repo_name}}",

tests/data/test_package_generation/pyproject.toml

@@ -26,6 +26,10 @@ dynamic = [
 ]
 keywords = [
 ]
+license = "MIT"
+license-files = [
+    "LICENSE.md",
+]
 name = "cookiecutter-test"
 optional-dependencies = {dev = [
     "build",
@@ -46,7 +50,6 @@ optional-dependencies = {dev = [
 ]}
 readme = "README.md"
 requires-python = ">=3.11"
-license.file = "LICENSE.md"
 urls.homepage = "https://github.com/test-user/cookiecutter-test"
 
 [tool.coverage]

{{cookiecutter.project_slug}}/LICENSE.md

@@ -23,7 +23,7 @@ COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-{%- elif cookiecutter.license == "BSD-3" -%}
+{%- elif cookiecutter.license == "BSD-3-Clause" -%}
 
 Copyright (c) {% now 'utc', '%Y' %}, {{cookiecutter.author_given_names}}
 {{cookiecutter.author_family_names}} All rights reserved.

{{cookiecutter.project_slug}}/README.md

@@ -15,7 +15,7 @@
 [documentation-link]:       {{cookiecutter.__repo_url}}/actions/workflows/docs.yml
 {%- if cookiecutter.license == "MIT" %}
 [license-badge]:            https://img.shields.io/badge/License-MIT-yellow.svg
-{%- elif cookiecutter.license == "BSD-3" %}
+{%- elif cookiecutter.license == "BSD-3-Clause" %}
 [license-badge]:            https://img.shields.io/badge/License-BSD_3--Clause-blue.svg
 {%- elif cookiecutter.license == "GPL-3.0" %}
 [license-badge]:            https://img.shields.io/badge/License-GPLv3-blue.svg

{{cookiecutter.project_slug}}/pyproject.toml

@@ -29,6 +29,10 @@ dynamic = [
 ]
 keywords = [
 ]
+license = "{{cookiecutter.license}}"
+license-files = [
+    "LICENSE.md",
+]
 name = "{{cookiecutter.project_slug}}"
 optional-dependencies = {dev = [
     "build",
@@ -49,7 +53,6 @@ optional-dependencies = {dev = [
 ]}
 readme = "README.md"
 requires-python = ">={{cookiecutter.min_python_version}}"
-license.file = "LICENSE.md"
 urls.homepage = "{{cookiecutter.__repo_url}}"
 
 [tool.coverage]