Network Access documentation (#335)

* Update basic-concepts.md

* Update command-line-tool.md

Author: khaiyra

src/topics/command-line-tool.md

@@ -63,3 +63,23 @@ and in the [Outputs](../topics/outputs.md) sections.
 %
 % - Spaces in commands https://github.com/common-workflow-language/user_guide/issues/39
 % - Arguments (tell the reader the different use cases for arguments and inputs, tell them there is a section about inputs)
+
+
+## Network Access
+This indicates whether a process requires outgoing IPv4/IPv6 network access.
+If a command-line tool is written manually in CWL v1.1+, there is a need to 
+specify when network access is required.
+
+```cwl
+cwlVersion: v1.2
+class: CommandLineTool
+
+requirements:
+  NetworkAccess:
+     networkAccess: true
+```
+
+```{note}
+CWL v1.0 command-line tools that are upgraded to v1.1 
+or v1.2 get Network Access automatically.
+```