Update package version to 4.21.1

pkg.info

@@ -1,6 +1,6 @@
 name: gtkmm4
 description: The official C++ interface for the popular GUI library GTK (version 4)
-version: 4.21.0
+version: 4.21.1
 revision: 1
 url: https://www.gtkmm.org/
 license: LGPL2.1-or-later
@@ -22,3 +22,8 @@ depends:
 make_depends:
   - meson
   - mm-common
+downloads:
+  - url: https://download.gnome.org/sources/gtkmm/${BPM_PKG_VERSION%.*}/gtkmm-${BPM_PKG_VERSION}.tar.xz
+    extract_to: ${BPM_SOURCE}
+    extract_strip_components: 1
+    checksum: 3d404e98f446f847587e0c290e62fabdc93ccd8c08c913ae0dc21ed5e4b89c93

source.sh

@@ -2,16 +2,6 @@
 # BPM Expects the source code to be extracted into the automatically created 'source' directory which can be accessed using $BPM_SOURCE
 # BPM Expects the output files to be present in the automatically created 'output' directory which can be accessed using $BPM_OUTPUT
 
-DOWNLOAD="https://download.gnome.org/sources/gtkmm/${BPM_PKG_VERSION%.*}/gtkmm-${BPM_PKG_VERSION}.tar.xz"
-FILENAME="${DOWNLOAD##*/}"
-
-# The prepare function is executed in the root of the temp directory
-# This function is used for downloading files and putting them into the correct location
-prepare() {
-  wget "$DOWNLOAD"
-  tar -xvf "$FILENAME" --strip-components=1 -C "$BPM_SOURCE"
-}
-
 # The build function is executed in the source directory
 # This function is used to compile the source code
 build() {