adjust version documentation
-# gardenlinux epoch (days since 2020-04-01) - defines dependency snapshot date
-# use `today` to build against latest
+# the version defined in this file specifies the _next_ release version of gardenlinux, as well as
+# (implicitly) the gardenlinux epoch (days since 2020-04-01) to use as dependency timestamp.
+# use `today` to build against latest (release version will be `<epoch>.0` (e.g. 42.0))
today
