fix: Set correct development status (#687)

Author: alrex

ext/opentelemetry-ext-django/setup.cfg

@@ -23,7 +23,7 @@ url = https://github.com/open-telemetry/opentelemetry-python/tree/master/ext/ope
 platforms = any
 license = Apache-2.0
 classifiers =
-    Development Status :: 3 - Beta
+    Development Status :: 4 - Beta
     Intended Audience :: Developers
     License :: OSI Approved :: Apache Software License
     Programming Language :: Python