Add release checksums for opusfile 0.1 and 0.2.

Add checksums for the first two source releases for completeness.
These are copied from and verified against downloads.xiph.org.

releases.sha2

+8071b968475c1a17f54b6840d6de9d9ee20f930e827b0401abe3c4cf4f3bf30a  opusfile-0.1.tar.gz
+b4a678b3b6c4adfb6aff1f67ef658becfe146ea7c7ff228e99543762171557f9  opusfile-0.2.tar.gz
 094b789ee975fbc5ac706b14e5c83f12b92448fa0a55c8a9f7d79afa7f962aae  opusfile-0.1-win32.zip
 33521cef2ef341a938b386439e9879d3e8e916638ffdd5a7d11e09172f307d35  opusfile-0.2-win32.zip
 4248927f2c4e316ea5b84fb02bd100bfec8fa4624a6910d77f0af7f0c6cb8baa  opusfile-0.3.tar.gz