Revert "release: updating changelogs and version to 0.13b0 (#1129)"

This reverts commit 8c9b534e35.

exporter/opentelemetry-exporter-zipkin/CHANGELOG.md

@@ -2,10 +2,6 @@
 
 ## Unreleased
 
-## Version 0.13b0
-
-Released 2020-09-17
-
 - Add support for OTEL_EXPORTER_ZIPKIN_ENDPOINT env var. As part of this change, the 
   configuration of the ZipkinSpanExporter exposes a `url` argument to replace `host_name`,
   `port`, `protocol`, `endpoint`. This brings this implementation inline with other

exporter/opentelemetry-exporter-zipkin/setup.cfg

@@ -40,8 +40,8 @@ package_dir=
 packages=find_namespace:
 install_requires =
     requests ~= 2.7
-    opentelemetry-api == 0.13b0
-    opentelemetry-sdk == 0.13b0
+    opentelemetry-api == 0.13dev0
+    opentelemetry-sdk == 0.13dev0
 
 [options.packages.find]
 where = src

exporter/opentelemetry-exporter-zipkin/src/opentelemetry/exporter/zipkin/version.py

@@ -12,4 +12,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-__version__ = "0.13b0"
+__version__ = "0.13dev0"