Update package version to 4.21.0

pkg.info

@@ -1,7 +1,13 @@
 name: libtasn1
 description: The ASN.1 library used in GNUTLS
-version: 4.20.0
+version: 4.21.0
+revision: 1
 url: https://www.gnu.org/software/libtasn1/
 license: GFDL1.3-or-later,GPL3-or-later,LGPL2.1-or-later
 architecture: any
 type: source
+downloads:
+  - url: https://ftpmirror.gnu.org/gnu/libtasn1/libtasn1-${BPM_PKG_VERSION}.tar.gz
+    extract_to: ${BPM_SOURCE}
+    extract_strip_components: 1
+    checksum: 1d8a444a223cc5464240777346e125de51d8e6abf0b8bac742ac84609167dc87

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://ftpmirror.gnu.org/gnu/libtasn1/libtasn1-${BPM_PKG_VERSION}.tar.gz"
-FILENAME="${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() {