Switch license to MIT and add license files (#958)

* Switch license to MIT and add license files

Changed the package license from GPL-3 to MIT in DESCRIPTION, added LICENSE and LICENSE.md files, and updated .Rbuildignore to exclude LICENSE.md. This aligns the project with the MIT license and provides the required documentation.

* `usethis::use_tidy_description()` (GitHub Actions)

* Update license note to reflect MIT License

Changed the license reference from GPL-3 to MIT License and clarified the description of bundled third-party components in LICENSE.note.

Author: karangattu

.Rbuildignore

@@ -35,3 +35,4 @@
 ^_dev$
 ^vignettes/articles$
 ^pkgdown$
+^LICENSE\.md$

DESCRIPTION

@@ -43,7 +43,7 @@ Description: Create and customize interactive maps using the 'Leaflet'
     JavaScript library and the 'htmlwidgets' package. These maps can be
     used directly from the R console, from 'RStudio', in Shiny
     applications and R Markdown documents.
-License: GPL-3
+License: MIT + file LICENSE
 URL: https://rstudio.github.io/leaflet/,
     https://github.com/rstudio/leaflet
 BugReports: https://github.com/rstudio/leaflet/issues
@@ -59,8 +59,8 @@ Imports:
     methods,
     png,
     raster (>= 3.6.3),
-    rlang,
     RColorBrewer,
+    rlang,
     scales (>= 1.0.0),
     sf (>= 0.9-6),
     stats,
@@ -78,9 +78,9 @@ Suggests:
     sp,
     terra,
     testthat (>= 3.0.0)
-Config/testthat/edition: 3
 Config/Needs/website: dplyr, ncdf4, rnaturalearth, tidyverse/tidytemplate
+Config/testthat/edition: 3
 Encoding: UTF-8
 LazyData: true
-RoxygenNote: 7.3.2
 Roxygen: list(markdown = TRUE)
+RoxygenNote: 7.3.2

LICENSE

@@ -0,0 +1,2 @@
+YEAR: 2025
+COPYRIGHT HOLDER: leaflet authors

LICENSE.md

@@ -0,0 +1,21 @@
+# MIT License
+
+Copyright (c) 2025 leaflet authors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR 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.

LICENSE.note

@@ -1,9 +1,9 @@
-The leaflet package as a whole is distributed under GPL-3 (GNU GENERAL PUBLIC
-LICENSE version 3).
+The leaflet package as a whole is distributed under the MIT License (see the
+top-level LICENSE file).
 
-The leaflet package includes other open source software components. The following
-is a list of these components (full copies of the license agreements used by
-these components are included below):
+The leaflet package bundles certain third-party open source software
+components. The following is a list of these components (full copies of their
+license agreements are included below):
 
 - Leaflet (JavaScript library), https://github.com/Leaflet/Leaflet
 - leaflet-measure, https://github.com/ljagis/leaflet-measure