Conditionally create server spans for flask (open-telemetry#828)

* Making span as internal in presence of a span in current context

* Updating changelog

* Removing extra print statements

* Resolving comments: Setting current context as parent in its presence

* Ignoring pylint check as django.conf.urls.url is removed in django 4.0
Django release notes: https://docs.djangoproject.com/en/4.0/releases/4.0/

* Removing changes in django files

Author: ashu658

CHANGELOG.md

@@ -33,6 +33,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - `opentelemetry-instrumentation-tornado` Add support instrumentation for Tornado 5.1.1
   ([#812](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/812))
+
+- `opentelemetry-instrumentation-flask` Flask: Conditionally create SERVER spans
+  ([#828](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/828))
 
 ## [1.7.1-0.26b1](https://github.com/open-telemetry/opentelemetry-python/releases/tag/v1.7.0-0.26b0) - 2021-11-11