Bump project version to 0.3.0

Version 0.3.0 contains handling for additional path-based version
specifiers in yarn.lock.

Signed-off-by: Taylor Madore <tmadore@redhat.com>

setup.cfg

@@ -1,6 +1,6 @@
 [metadata]
 name = pyarn
-version = 0.2.0
+version = 0.3.0
 description = Yarn JS package manager lockfile parser
 long_description = file: README.md
 long_description_content_type = text/markdown