On each release:
* update CHANGELOG
* bump the version number in the .cabal file (including in the "this" repository spec)
* cabal upload a release tarball
* darcs tag with the version number

To build a release tarball:
cabal configure
./dist/setup/setup sdist
tar xf dist/encoding-version.tar.gz
rm -r encoding-version/dist
tar --format=ustar -czf dist/encoding-version.tar.gz encoding-version
rm -r encoding-version
cabal upload dist/encoding-version.tar