Change *BASE* to BASE to fix "earmuffs" warning

[webcoyote]

Hi, and thanks for creating the fressian-cljs library. I've made a trivial change to the library to fix a warning message that occurs during the shadow-cljs build process:

------ WARNING #1 - :non-dynamic-earmuffed-var ---------------------------------
Resource: fressian_cljs/adler32.cljs:3:1
*BASE* not declared dynamic and thus is not dynamically rebindable, but its name suggests otherwise. Please either indicate ^:dynamic *BASE* or change the name

Alternatively, *BASE* could be declared with ^:dynamic.

I would appreciate it if you would merge this, and bump the version number, I guess, as right now this warning pops up every time we make a build. Thanks!