Change passive to active voice in workflow.md

Fix sentence for consistent voice throughout and across documents

Author: Amanda Butler

docs/reference/contributing/guidelines/workflow.md

@@ -63,7 +63,7 @@ Pull requests on GitHub have to meet the following requirements to keep the code
 
 #### Release versioning
 
-Mbed OS versioning can be found at [How We Release Arm Mbed OS](https://os-doc-builder.test.mbed.com/docs/development/introduction/how-we-release-arm-mbed-os.html).
+You can find Mbed OS versioning at [How We Release Arm Mbed OS](/docs/development/introduction/how-we-release-arm-mbed-os.html).
 
 ### Pull request categories