replace dashes (-) with tildes (~) in deb package version numbers

Dashes hold special significance in the Debian package versions. Versions that contain a dash and should be considered an earlier version (e.g. pre-releases) may actually be ordered as later (e.g. 12.0.0-rc.6 > 12.0.0). We'll work around this by replacing dashes (`-`) with tildes (`~`). We'll also move to replacing invalid characters with underscores (`_`).

Fixes #396

/cc @opscode/release-engineers @juliandunn @psychonaut