community/py3-libarchive-c: fix checksum
The cached tarball with the same package version has a different checksum from upstream. Rename the tarball filename to re-download the tarball from upstream and resolve checksum mismatch error.
Error found on the 3.21 riscv64 builder.
>>> py3-libarchive-c: Fetching https://distfiles.alpinelinux.org/distfiles/v3.20/python-libarchive-c-5.1.tar.gz
Connecting to distfiles.alpinelinux.org (172.105.82.32:443)
saving to '/var/cache/distfiles/v3.21/python-libarchive-c-5.1.tar.gz.part'
python-libarchive-c- 100% |********************************| 48816 0:00:00 ETA
'/var/cache/distfiles/v3.21/python-libarchive-c-5.1.tar.gz.part' saved
>>> py3-libarchive-c: Fetching https://distfiles.alpinelinux.org/distfiles/v3.20/python-libarchive-c-5.1.tar.gz
>>> py3-libarchive-c: Checking sha512sums...
python-libarchive-c-5.1.tar.gz: FAILED
sha512sum: WARNING: 1 of 1 computed checksums did NOT match