Bump to version 0.3.0 and update the NEWS file.

Author: atheriel

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: openmetrics
 Title: A 'Prometheus' Client for R Using the 'OpenMetrics' Format
-Version: 0.2.0
+Version: 0.3.0
 Authors@R: c(
   person("Aaron", "Jacobs", role = c("aut", "cre"),
          email = "atheriel@gmail.com"),

NEWS.md

@@ -1,4 +1,4 @@
-# openmetrics 0.2.0.9000
+# openmetrics 0.3.0
 
 ## Breaking Changes
 
@@ -13,6 +13,8 @@
 
 ## Other Improvements
 
+* The package now has its own hex logo.
+
 * Only generate the OpenMetrics format when the (preliminary) OpenMetrics
   content-type is passed in the `Accept` header. Otherwise, fall back on the
   Prometheus format and content-type (#3).