Rename 0.6 to 0.6alpha.

For the LuaRocks versioning algorithm,
0.6a > 0.6, but 0.6alpha < 0.6. It recognizes
"alpha" < "beta" < "rc", but other letter suffixes are
recognized as greater than numbers (e.g. 1.0k > 1.0g > 1.0).

Description.

LuaSec 0.5 Release.

LuaSec 0.4.1

LuaSec 0.4

LuaSec 0.3.3

LuaSec 0.3.2

LuaSec 0.3.1

LuaSec 0.3

LuaSec 0.2